REVISION OF THE GENUS ISCHYRUS LACORDAIRE (1842)
OF NORTH AND CENTRAL AMERICA
PAUL EDWARD SKELLEY
A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
Paul Edward Skelley
I thank my committee, R. E. Woodruff and M. C. Thomas,
Florida State Collection of Arthropods, and D. H. Habeck and
J. W. Kimbrough, University of Florida, for their guidance,
encouragement, assistance, and editorial comments for this
and many other studies. Without them I would never have
attained my goals. I thank M. A. Goodrich, Eastern Illinois
University, for assistance during this study and for his
continued support with other studies on the Erotylidae.
For loans of specimens, including types, I thank the
following people and their associated institutions: F. G.
Andrews, California State Collection of Arthropods; R. S.
Anderson, Canadian Museum of Nature; J. S. Ashe, R. W.
Brooks, and R. A. B. Leschen, Snow Entomological Museum,
University of Kansas; D. Azuma, Academy of Natural Sciences,
Philadelphia; A. O. Bachmann, Museo Argentino de Ciencias
Naturales; N. Berti, Museum National d'Histoire Naturelle,
Paris; R. L. Blinn, University of Missouri; M. Brancucci,
Naturhistorisches Museum Basel; R. L. Brown, Mississippi
State University; C. Carlton, University of Arkansas; E. D.
Cashatt, Illinois State Museum; R. D. Cave, Escuela Agricola
Panamericana, Tegucigalpa, Honduras; D. S. Chandler,
University of New Hampshire; F. A. Cholick, South Dakota
State University; S. M. Clark, West Virginia Department of
Agriculture; W. E. Clark, Auburn University; C. Covell,
University of Louisville, Kentucky; D. P. Cowan, Western
Michigan University; R. L. Davidson, Carnegie Museum of
Natural History; K. Desender, Institute Royale des Sciences
Naturalles de Belgique; M. A. Deyrup, Archbold Biological
Station; M. E. Douglas, Arizona State University; O. V.
Ferreira, FundaQ&o Oswaldo Cruz; R. W. Flowers, Florida A. &
M. University; W. A. Foster, University of Cambridge, United
Kingdom; P. H. Freytag, University of Kentucky; M. H. M.
Galileo, Museu de Cidncias Naturais, Porto Alegre, Brazil;
M. A. Goodrich, Eastern Illinois University; I. Goreyeb and
T. P. Chaves, Museu Paraense Emilio Goeldi; L. H. Herman,
American Museum of Natural History; M. W. Heyn, Clemson
University; F. Hieke, Museum fOr Naturkunde der Humboldt-
Universitdt zu Berlin; G. N. House, United States National
Museum; N. Johnson and P. W. Kovarik, Ohio State University;
D. H. Kavanaugh and R. Brett, California Academy of
Sciences; M. D. Kerley, Natural History Museum, London; B.
C. Kondratieff, Colorado State University; M. Kosztarab,
Virginia Polytechnic Institute and State University; S.
Krauth, University of Wisconsin; W. E. LaBerge and K. C.
McGriffen, Illinois Natural History Survey; P. K. Lago,
University of Mississippi; J. F. Lawrence, CSIRO, Canberra,
Australia; R. Lawson, Chadron State College; R. E. Lewis,
Iowa State University; J. K. Liebherr, K. E. M. Galley, and
J. V. McHugh, Cornell University; J. McNamara, Canadian
National Collection of Insects; J. E. McPherson, Southern
Illinois University; O. Merkl, Hungarian Natural History
Museum; C. R. Nelson, Brigham Young University; A. F.
Newton, Jr., and P. Parillo, Field Museum of Natural
History; D. NThez, Escuela Nacional de Ciencias Forestales,
Honduras; M. F. O'Brien, University of Michigan Museum of
Zoology; C. A. Olson, University of Arizona; G. Onore,
Pontificia Universidad Cat6lica de Ecuador; C. S. Parron,
North Carolina State University; S. Pratt, Museum of
Comparative Zoology, Harvard University; A. Provonsha,
Purdue University; B. C. Ratcliffe, University of Nebraska
State Museum; E. G. Riley, Texas A. & M. University; R. A.
Ronderos, Universidad Nacional de La Plata, Argentina; S.
Santiago, Universidad Nacional Aut6noma de M6xico; G.
Scherer, Zoologische Staatssammlung, Minchen; Y. Sedman,
Western Illinois University; D. Shpeley and D. A. Pollock,
Strickland Museum, University of Alberta; C. L. Smith,
University of Georgia, Athens; R. R. Snelling, Los Angeles
County Museum; C. A. Springer, Hastings College, Nebraska;
F. W. Stehr, Jr., Michigan State University; A. L. TerAn,
Fundaci6n Miguel Lillo, Tucuman, Argentina; R. E. Woodruff
and M. C. Thomas, Florida State Collection of Arthropods; R.
S. Zack, Washington State University; L. Zerche, Deutsches
Entomologisches Institut, Eberswalde-Finow.
I thank the following private collectors for allowing
me to study their collections: A. Allen, R. J. Barney, J. L.
Carr, J. M. Cicero, E. J. Ford, S. M. Fullerton, D. H.
Habeck, M. A. Ivie, D. H. Kavanaugh, P. K. Lago, R. A. B.
Leschen, R. W. Lundgren, S. McCleve, J. V. McHugh, R. F.
Morris, G. H. Nelson, T. K. Philips, R. Prange, W. Suter, R.
H. Turnbow, Jr., J. E. Wappes, and J. Watts.
For assistance in locating types, I thank W. A. Foster,
Cambridge University, United Kingdom; F. Hieke, Museum fur
Naturkund der Humboldt-Universitdt zu Berlin;
D. S. Horning, University of Sydney; M. D. Kerley, Natural
History Museum, London; G. C. McGavin, Oxford University.
For assistance with the scanning electron microscope
and specimen preparation techniques, I thank H. Cromroy and
W. Carpenter, University of Florida. For darkroom
assistance and other photographic reproductions, I thank J.
Lotz, Division of Plant Industry, Florida Department of
Agriculture and Consumer Services.
I thank E. Mayr, J. McCarthy, and E. Langosy, Harvard
University, for the support of an Ernst Mayr Grant, which
allowed me to study specimens in both the Crotch Erotylidae
Collection, Cambridge University, and the Natural History
Museum, London. This study would not have been completed
without their assistance.
I thank M. C. Thomas, Florida State Collection of
Arthropods, for assistance with computer graphic programs
used in the illustrations. I thank all of the personnel
(too numerous to mention) at the Florida Department of
Agriculture and Consumer Services, Florida State Collection
of Arthropods, for their support and tolerance during my
eight years of study.
If I have unknowingly omitted anyone, I thank them here
for their assistance.
Last, yet foremost, I thank my parents, Paul F. and
Antoinette, and my wife, Lucy, for their encouragement and
love over these many years.
TABLE OF CONTENTS
ACKNOWLEDGMENTS .................................. ........ iii
................... ............................ x
INTRODUCTION ............................................... 1
General Introduction ................................ 1
History ............................................. 2
Nomenclatural Status ............................... 6
Format of Species Accounts ......................... 8
Characters and Terminology ........................... 11
Basics .......................................... 11
Eye Facets ...
Body Shape ...
First Visible Abdominal Sternite ..............
Male Genitalia ................................
Female Genitalia ..............................
Materials and Methods ..............................
Locating Types ................................
Color Pattern Problems ........................
Rules of Thumb ................................
ISCHYRUS LACORDAIRE .....................................
ARTIFICIAL KEY TO SPECIES ...............................
SPECIES ACCOUNTS ........................................
Ischyrus aleator Boyle .............................
Ischyrus angularis Lacordaire ......................
Ischyrus auriculatus Lacordaire ....................
... .. .. ... .. .. ... .. .. ..
Ischyrus bogotae Crotch ...........................
Ischyrus boucardi Crotch ..........................
Ischyrus chacojae Gorham ..........................
Ischyrus collatinus Crotch ........................
Ischyrus distinguendus Lacordaire .................
Ischyrus dunedinensis Blatchley ...................
Ischyrus elegantulus Lacordaire ...................
Ischyrus ephippiatus Gorham .......................
Ischyrus episcaphulinus Gorham ....................
Ischyrus frontalis Lacordaire .....................
Ischyrus fulmineus Delkeskamp .....................
Ischyrus incertus Lacordaire ......................
Ischyrus insolens Crotch ..........................
Ischyrus pictus Gorham ............................
Ischyrus proximus Lacordaire ......................
Ischyrus quadripunctatus (Olivier) ................
Ischyrus quadripunctatus quadripunctatus (Olivier)
Ischyrus quadripunctatus chiasticus Boyle, New Stat
Ischyrus scriptus (Olivier) .......................
Ischyrus scutellaris Gorham .......................
Ischyrus septemsignatus Gorham ....................
Ischyrus tetrasticus Gorham .......................
Ischyrus tripunctatus Crotch ......................
Ischyrus undulatus Gorham .........................
Ischyrus vespertilio Lacordaire ...................
Ischyrus n. sp. 1 .................................
Ischyrus n. sp. 2 .................................
Ischyrus n. sp. 3 .................................
Ischyrus n. sp. 4 .................................
Ischyrus n. sp. 5 .................................
Ischyrus n. sp. 6 .................................
Ischyrus n. sp. 7 .................................
Ischyrus n. sp. 8 .................................
Ischyrus n. sp. 9 .................................
Ischyrus n. sp. 10 ................................
Ischyrus n. sp. 11 ................................
Ischyrus n. sp. 12 ................................
Ischyrus n. sp. 13 ................................
Ischyrus n. sp. 14 ................................
Ischyrus n. sp. 15 ................................
Ischyrus n. sp. 16 ................................
APPENDIX A: ISCHYRUS SPECIES NAMES .................... 308
APPENDIX B: COLLECTIONS STUDIED AND CODENS ............. 317
APPENDIX C: SPECIMEN LABEL DATA ........................ 320
LITERATURE CITED ....................................... 348
BIOGRAPHICAL SKETCH ...................................... 362
Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
REVISION OF THE GENUS ISCHYRUS LACORDAIRE (1842)
OF NORTH AND CENTRAL AMERICA
Paul Edward Skelley
Chairman: Robert E. Woodruff
Major Department: Entomology and Nematology
This revision treats all known species of the genus
Ischyrus Lacordaire occurring from Panama north. A key to
the species, descriptions and illustrations of terms used,
habitus and genitalic illustrations for all species,
distribution maps, detailed species descriptions, complete
synonymies, label data from specimens studied, and
comparisons with similar species are presented to aid in the
identification of specimens. A list of all names used in
combination with Ischyrus and their current status is
presented to prevent future homonyms. A total of 26, valid
previously described species is addressed, nine new
synonymies made, and 16 new species described.
The family Erotylidae is composed of fungus-feeding
beetles that vary in body size and color; many are
elaborately patterned. Recently published catalogs detail
the Old World species (Delkeskamp 1981; ChQj6 & ChQj6 1988,
1989, 1990). In contrast, Crotch's (1876) world revision
of the Erotylidae was the last study to cover the entire
New World fauna, but it provided no keys or illustrations
and few descriptions. Since Crotch's time, the New World
erotylid fauna has been studied intermittently, with
scattered regional studies, catalogs, and species
descriptions. Most New World erotylid genera have no
The purpose of this study is to begin bringing the
nomenclature of the New World Erotylidae into the 20th
century and to publish the results in a manner that will
enable entomological students to identify their specimens.
"Progress in Natural History necessarily starts from a
basis of species, and until these are accurately described
so that others can arrive at a knowledge of them no great
advance is possible" (Horn 1887:7).
Nomenclatural changes and lectotype designations made
in this dissertation are not to be considered valid until
they are published. Holotypes are not selected and names
are not proposed for the new species to avoid potential
The first described member of the genus Ischyrus
Lacordaire is Erotylus quadripunctatus Olivier (1792). The
first use of the name Ischyrus was by Chevrolat in fascicle
5 of the second edition of Dejean's catalog (1836).
Because most of the second edition was burned in a fire,
the third edition of the Dejean catalog (1837) was
immediately printed. (See Madge, 1988, for dates of
publication and history of the Dejean catalogs.)
Dejean's (1836, 1837) catalogs were among the first
works to split the genus Erotylus Fabricius (1775) into
more manageable, related taxa. Species and generic
concepts were in their infancy during the early 1800s. For
the Erotylidae, Dejean's genera appear to be groups of
species with similar body size and color. This is evident
in the proposed genus Ischyrus Chevrolat containing large
dull-black species, Mycotretus Chevrolat containing smaller
species with yellow and black color patterns, and Lybas
Chevrolat containing species that were oval and solid red.
Dejean's catalogs were simply checklists of his collection
in which many generic and specific names were proposed.
Because the Dejean names lacked descriptions, they were
often ignored by early taxonomists.
The next use of the name Ischyrus was by Falderman
(1837) in describing Ischyrus lepidus, presently a member
of Triplax Herbst (1793) (fide ChOj6 & ChOj6 1990). The
name Ischyrus was then used as a subgroup of Erotylus
Fabricius (1775) by Gu6rin-M6neville (1841) in describing
E. (Ischyrus) nebulosus, presently a member of
Brachysphaenus Lacordaire (1842) (fide Crotch 1876). These
uses of "Ischyrus" illustrate early workers' attempts at
placing new species into taxa based on superficial
Lacordaire (1842) was the first person to provide a
description of the genus Ischyrus, for which he gave credit
to Chevrolat in Dejean (1836) as the author of the name.
He moved many previously described species into Ischyrus
and described 17 new species. Unfortunately, Lacordaire
did not designate a type species for Ischyrus.
Lacordaire split the genus into two divisions. The
first division contained species with larger body size and
strongly keeled prosternum, mostly species listed in the
Dejean catalogs as Ischyrus Chevrolat. The second division
contained species with smaller body size and a weakly
keeled prosternum, mostly species listed under Mycotretus
Chevrolat in the Dejean catalogs, including Erotylus
quadripunctatus Olivier. Lacordaire based his generic
concepts on reasonably sound morphological features that
are still in use. He also maintained many previously
published species names that had not been described [nomina
nuda]. With his descriptions, Lacordaire became the author
of these names.
Subsequent authors, Guerin-Meneville (1844) and
Erichson (1847), used Lacordaire's generic names and
described seven additional species of Ischyrus.
Crotch (1873b) separated Lacordaire's divisions into
distinct genera. The first division, containing species of
larger size, he named Megischyrus. The second division,
containing species of smaller size, he maintained as
Ischyrus, crediting Lacordaire as the describer and noting
the original use of the name by Chevrolat in Dejean (1836).
At that time, it was common to give credit for a name to
the first describer of the taxon and not to the author of
that name. Following this trend, Crotch cited it as
In 1873 Crotch received a grant to visit tropical
Australia and adjacent islands to collect natural history
specimens. Before his departure from Cambridge, U.K., he
placed his collection and manuscript in the care of E. W.
Janson. Unfortunately, Crotch became ill and died in 1874
while in the U.S.A. Edward W. Janson put Crotch's
manuscript into final form and published it. Numerous
notes within the revision are undoubtedly those of Janson.
Without Crotch's input, many of the species problems
alluded to within the text were left unresolved. This
"revision" is simply an annotated catalog of the species
previously described, with brief descriptions of the new
species. Yet, it has been the basis for all subsequent
studies of the family. The name Ischyrus Lacordaire, as
cited and used in Crotch's revision, was accepted and used
by all subsequent workers, with the exception of Alvarenga
(1965, discussed below). Crotch (1876) listed 44 species
of Ischyrus, 13 of which were new species.
Ischyrus Lacordaire (sensu Crotch) has been referenced
in a multitude of papers and texts. Many of these are
simply species descriptions, regional studies, catalogs,
general entomological texts, or biological accounts. These
are too numerous to list here, but they can be found in the
species accounts of this revision.
Some of the more important references are worth
noting. Gemminger and Harold's (1876) Catalogus
Coleopterorum was published shortly after Crotch's revision
and contains the names as used by Crotch. Gorham (1887-
1899), in the Biologia Centrali-Americana, gave accounts
for 22 species of Ischyrus that included 10 new species.
Kuhnt (1909, 1911) provided two catalogs, the first of
which contained a simple grouping of the species by various
color pattern characters.
The most recent catalog of the genus Ischyrus
Lacordaire is Blackwelder's (1945) Checklist of the
Coleopterous Insects of Mexico, Central America, the West
Indies, and South America, which lists 56 names. Boyle
(1954, 1956) revised the family Erotylidae for America,
north of Mexico, thoroughly describing the genus Ischyrus
and one new species.
The most recent paper of importance to the genus
Ischyrus Lacordaire is Alvarenga (1965). Following current
nomenclatural rules, Alvarenga realized that Crotch (1873b)
had incorrectly applied the name Ischyrus and selected an
invalid type species. Alvarenga made some major changes in
the standing of the names Ischyrus and Megischyrus, which
are discussed in the following section.
Before the present study, there were 65 valid species
placed in the genus Ischyrus Lacordaire. This study
addresses 26 of these, synonymizes 9, and describes 16 new
species. This brings the total to 72 species. (See
Appendix A for a list of all specific names used in
association with Ischyrus and their current status.)
The early nomenclature of this genus is typical for
many taxa, with names being proposed and ignored. The name
Ischyrus Chevrolat in Dejean (1836) is a nomen nudum (name
without description) and was not valid in the opinion of
some early workers. Thus, the first use of the name to be
accompanied by a description was the valid name. Crotch
(1873b) undoubtedly had this in mind when he raised
Lacordaire's divisions to full generic status. Crotch
proposed the name Megischyrus for Lacordaire's first
division, designating Erotylus undatus Olivier as the type
species. Crotch retained the name Ischyrus for the second
division, crediting Lacordaire as the first describer of
the genus, and designated Erotylus quadripunctatus Olivier
as the type species. This was accepted and used by all
subsequent workers until Alvarenga (1965) found some errors
in the type designations and credits for these genera.
According to the current International Code of
Zoological Nomenclature (1985) the first valid use of a
name is to be followed--the Law of Priority. Before 1931,
the first use of a generic name is valid if it is followed
by a description or has a valid species name listed under
it, an indication. Also, in designating a type species for
a genus subsequent to its first use, the reviser
designating the type must choose a species from those
originally included within the genus (as indicated by
Barber & Bidwell 1940). This makes the Dejean catalogs
(1836, 1837) the first valid uses of the generic name
Ischyrus, and the type species should have been chosen from
the species listed within it.
According to these rules, Crotch (1873b) had
incorrectly chosen the type species of Ischyrus, because
Erotylus quadripunctatus was not listed in Dejean (1836) as
Ischyrus. Erotylus undatus Olivier was listed under the
name Ischyrus Chevrolat in Dejean (1836). Crotch chose
Erotylus undatus as the type species of his genus
Megischyrus. This makes Megischyrus Crotch an objective
synonym of Ischyrus Chevrolat, leaving Ischyrus Lacordaire
(sensu Crotch) without a valid name.
Discovering these problems, Alvarenga (1965) corrected
them by synonymizing Megischyrus Crotch under Ischyrus
Chevrolat, designating Erotylus undatus Olivier as the type
species. For Ischyrus Lacordaire (sensu Crotch) he
proposed the name Micrischyrus, designating Erotylus
quadripunctatus Olivier as the type species. In essence,
he discarded one name, moved another, and proposed a third.
In my opinion, Alvarenga's actions were not fully
justifiable because they create unnecessary confusion. The
main purpose of the International Code of Zoological
Nomenclature is to stabilize nomenclature, as stated in its
preamble. The code has provisions (Article 79) to conserve
long-standing, widely accepted names like Megischyrus
Crotch and Ischyrus Lacordaire (sensu Crotch). Therefore,
a proposal has been submitted to the International
Commission of Zoological Nomenclature (Skelley & Goodrich,
in press) to conserve these names by suppressing all uses
and indications of the name Ischyrus prior to Ischyrus
Lacordaire (1842). Pending the ruling of the Commission, I
am using the name Ischyrus Lacordaire (sensu Crotch), in
preference to Micrischyrus Alvarenga, as the name for the
genus studied in this revision.
Format of Species Accounts
Title. This heading is the valid name for the species
to be discussed.
Synonymy. This section lists all combinations of the
specific name and any synonyms of the valid name. These
are organized in the following manner: Genus species
describer date:page [comments], author of the synonymy or
combination date:page. Example: Engis variegata Dejean
1821:45 [nomen nudum], Gemminger & Harold 1876:3691.
Diagnosis. This section lists the set of characters
separating the species under consideration from all known
species in the genus.
Description. This section is a detailed description
of the species being discussed. It is organized in the
following manner: body measurements, overall appearance,
color pattern, head and antenna, visible mouthparts,
pronotum, scutellum, elytra, prosternum, mesosternum,
metasternum, first visible abdominal sternite, male
genitalia, female genitalia, stridulatory files, sexual
dimorphisms. Legs are not described because no characters
of use at the species level were found.
Variation. This section is a discussion of the color
pattern or morphological features that vary from specimen
to specimen in the species.
Type. Here I list the type specimens for all species
names appearing in the synonymy, their label data, type
locality (if not on their labels), current location, sex,
and if they were studied.
Label data for type specimens are given in the
following manner: "/ label data/ [my comments] label data/"
[XXXX]. The quotation marks, ", indicate the beginning
and ending of the data. The slash marks, /, indicate the
beginning and ending of an individual label. My comments
are placed in brackets, [ ], and usually indicate paper
color or label shape. When no comment is made, the paper
is white. After the label data are presented, a coden is
given in brackets, [XXXX], for the institution (see
Appendix B) where the specimen it is currently located.
Many species needed lectotypes designated. A red
"lectotype" label was placed on these specimens and dated
when they were designated as the "type."
Type specimens of previously described species were
dissected only if it was absolutely necessary to solve a
species problem. Since this was such a rare occurrence,
determining the sex of the types was accomplished using
external characters. In some cases, where sexual
dimorphism is distinct, the determination was easy. In
most cases, when the sex was unclear, it is listed as "not
Specimens examined. Here I list the label data for
all specimens studied, if there were fewer than ten
records. Species with more than ten collection records
have their data presented in tabular form in Appendix C to
help keep the text uncluttered and to present it in a more
Distribution. A brief account of the known geographic
distribution of the species is presented. A map is
provided for each species to illustrate the distribution.
Etymology. An attempt is made to present what the
species epithet means and possibly why the original author
chose it. This is included more for historical purposes
and may help the reader remember the name. Brown's (1985)
Composition of Scientific Words was an indispensable
reference in this research.
Taxonomic notes. This section includes nomenclatural
aspects that need clarification. I present some unsolved
problems of taxonomic importance indicating that this
revision is just a beginning.
Biologv. This section is included only for the few
species where some biological or life history data are
Remarks. This section contains statements on similar
species and how to separate them from other species being
References. This section lists the references where
the species name occurs. Each species name appearing in
the synonymy is listed separately to aid in future
literature searches for specific names other than the valid
Characters and Terminology
Most general terms follow the meaning presented in The
Torre-Bueno Glossary of Entomology (Nichols & Schuh 1989).
Terms for the genitalia follow Sharp and Muir (1912),
Tanner (1927), and Boyle (1956). Some characters and terms
need further explanation, as follows.
Eye facet size, coarse vs. fine, is used to separate
many genera in the Triplacinae. This character is based on
the relative size and distinctiveness of the eye facets in
relation to the head. Coarse facets (Fig. la) are larger
and more prominent, often bulging from the surface. Fine
facets (Fig. Ib) are smaller and less prominent, with a
smoother eye surface. There are many species that are
intermediate in facet development, making this character
difficult to interpret.
The puncture size is compared with the eye facet:
facet diameter to puncture diameter. Most Ischyrus species
have coarse punctation where the punctures are as large or
larger in diameter than a facet.
Punctures can be normal, impressed, or foveate. A
normal puncture appears like a simple pinprick. Impressed
punctures are deep punctures, usually with a rounded edge
and bottom. Foveate punctures are large, shallow, flat-
bottomed punctures, usually with a distinct edge.
The body is generally covered with a hexagonal micro-
sculpturing. Variations in the strength of this
microreticulation change the surface from shiny to dull and
are visible to the naked eye.
Figure 1. Dorsal view of heads showing eyes: a.) Ischyrus
q. quadripunctatus (Olivier) with coarsely faceted
eyes, line = 0.5 mm; b.) Tritoma atriventris LeConte
with finely faceted eyes, line = 0.38 mm. The arrow
points to the ocular stria.
Most of the species are flattened to slightly convex
dorsally; vespertilio Lacordaire and duponti Lacordiare are
convex dorsally (Fig. 2a, 2b). Most parallel-sided bodies
(Fig. 2c) are flattened dorsally. Most elongate bodies
have the sides parabolically rounded (Fig. 2d) and are
slightly convex above. Oval bodies (Fig. 2e) are rounded
on the sides and can be flattened or convex dorsally.
Ovoid bodies are egg-shaped (Fig. 2f) and wider anteriorly
and can be flattened or convex dorsally.
Color patterns are the most useful characters in the
recognition of species. Understanding the terms for
various aspects of the color pattern is essential in using
the key (Fig. 3).
A band is a wide transverse marking, wider than long.
A stripe is a longitudinal marking, longer than wide. A
spot is a small marking, usually circular or elongate. I
use the term "fascia" to mean a band that may be broken by
additional markings. A free spot is not connected to any
margin. A tooth-like spot is a triangular spot connected
to a margin.
The color patterns of most species are variations of a
basic pattern. I have named the components of the pattern
in reference to its position on the body (Fig. 4): anterior
pronotal, free pronotal, basal pronotal, pronotal hind
angle, humeral, subhumeral, scutellar, elytral suture,
Figure 2. Ischyrus body shapes: a.) flattened;
b.) convex; c.) parallel-sided; d.)
elongate; e.) oval; f.) ovoid.
Figure 3. Diagrammatic representation
of color pattern terms: B = band,
F = fascia, FSp = free spot, Sp =
spot, St = stripe, TSp = tooth-
Figure 4. Diagrammatic representation of a
generalized color pattern indicating
spot names: Ae = apical elytral, Ap =
anterior pronotal, Bp = basal pronotal,
Ce = central elytral, Es = elytral
suture, Fp = free pronotal, Hu =
humeral, Le = lateral elytral, Pha =
pronotal hind angle, Shu = subhumeral,
Sc = scutellar, Sc + Hu = basal elytral
band, Ce + Le = central elytral band.
central elytral, lateral elytral, and apical elytral. When
the scutellar and humeral spots are connected, they make up
the basal elytral band. When the central and lateral
elytral spots are connected, they make up the central
The dorsal surface of the head has relatively few
useful characters. On each side of the vertex following
the margin of the eye is a line or shallow groove, the
ocular stria (Fig. 1). Its length appears to be useful at
generic levels and is commented upon for future reference.
Since this line is shorter than the eye length in the vast
majority of Ischyrus, its length is given as a decimal that
indicates how far forward the line reaches on the eye. For
example, it could reach "0.75 distance to the anterior
angle of the eye," which means the line stops 3/4 of the
distance from the base to the anterior angle of the eye.
In Figure la, the ocular stria stops at the anterior angle.
The head size vs. eye size is given as a proportion:
head width between eyes = "N" eye widths (Fig. 5). The
smaller the eyes or the wider the head, the larger the
The base of the head often has structures which have
been called stridulatory files (Alexander et al. 1963;
Arrow 1924, 1925, 1942; Delkeskamp 1959). These structures
appear as iridescent spots under a dissecting microscope.
Study with the scanning electron microscope shows them to
Figure 5. Diagrammatic dorsal view of
a head showing the measurements
used for determining the ratio of
head to eye width; dorsal head
width between eyes = y/x times
be patches of parallel ridges. Even though these have been
called stridulatory, I have found no statement about the
sound produced. They appear only on males in some species
and on both sexes in others. The exact function of these
structures is unknown.
Representative species' antennae are illustrated on a
single plate for ease in comparison (Fig. 6). If a species
antenna is not illustrated, a reference is given to the
antenna that is most similar: "(similar to Fig. X)", where
"X" is the figure number.
The shape and proportions of the maxillary and labial
palp terminal segments are important for species
distinctions. These are illustrated on a single plate
(Fig. 7) for ease in comparing shapes and proportions.
This plate illustrates the palpi of representative species
to show the basic forms. The descriptions of species with
similar palpi have the statement "(similar to Fig. X),"
which refers to the figure "X" that is most similar to that
seen in the species being discussed.
The "triangular mentum" is a characteristic of
Ischyrus. The "triangle" is a sunken area of the mentum
surrounded by a ridge (Fig. 8). The triangular sunken area
is the mental plate. The ridge surrounding the plate is
the mental ridge; it is often extended forward at the
middle as a sharp divider between the labial palps. This
projection is called the medial ridge extension. As with
palp terminal segments, representative menta are
Figure 6. Antennae, line = 1.0 mm: a.) Ischyrus
distinguendus Lacordaire; b.) I. n. sp. 2; c.) I.
insolens Crotch; d.) I. bogotae Crotch; e.) I.
angularis Lacordaire; f.) I. q. quadripunctatus
(Olivier); g.) I. n. sp. 3; h.) I. n. sp. 4; i.) I.
n. sp. 6; j.) I. n. sp. 5; k.) I. n. sp. 1; 1.) I.
n. sp. 9; m.) I. n. sp. 14; n.) Megischyrus zonalis
(Lacordaire); o.) Megischyrus sp.
Figure 7. Terminal segments of labial palp (left) and
maxillary palp (right), line = 0.33 mm: a.)
Ischyrus distinguendus Lacordaire; b.) I. n. sp.
2; c.) I. insolens Crotch; d.) I. bogotae Crotch;
e.) I. septemsignatus Gorham; f.) I. q.
quadripunctatus (Olivier); g.) I. n. sp. 3; h.)
I. undulatus Gorham; i.) I. n. sp. 4; j.) I. n.
sp. 6; k.) I. n. sp. 7; 1.) I. n. sp. 5; m.) I.
aleator Boyle; n.) I. n. sp. 1; o.) I. n. sp. 9;
p.) I. ephippiatus Gorham; q.) I. tripunctatus
Figure 8. Menta, line = 0.33 mm: a.) Ischyrus
distinguendus Lacordaire; b.) I. n. sp. 2; c.)
I. insolens Crotch; d.) I. bogotae Crotch; e.)
I. n. sp. 3; f.) I. n. sp. 4; g.) I. n. sp. 6;
h.) I. n. sp. 5; i.) I. aleator Boyle; j.) I.
ephippiatus Gorham; Lp = labial palp, P =
mental plate, R = mental ridge, Re = mental
ridge medial extension.
illustrated on a single plate (Fig. 8) and are often
referred to in the text as "(similar to Fig. X)."
Except for color patterns mentioned above, the elytra
have few useful characters. One is the number of elytral
striae and the strength of the strial punctures. Most
species have seven complete striae; stria I next to the
elytral suture, striae V and VI originating at the humerus.
Stria VIII on most species is reduced to a short row of
punctures visible at the basal quarter under the humerus
and/or the apical quarter near the lateral edge of each
elytron. Two species (I. n. sp. 6 & I. n. sp. 7) have
stria VIII complete, one species (I. n. sp. 1) has parts of
stria IX visible.
The size of the strial interval punctures is variable
from species to species. In the majority of species the
punctures are small and obscured in the microsculpturing.
In a few other species they are large and distinct,
occasionally obscuring the strial punctures.
A "line" refers to a ridge or fine groove on a
sclerite that is not a suture, but probably has some
supportive function. These lines surround the coxae and
often extend onto the sclerite (Fig. 9). The term "coxal
line" is used in reference to the line on the median side
of the coxa. The lines anterior or posterior to the coxae
are referred to by the structure they are on or near; e.g.,
Figure 9. Ventral view of a.) Ischyrus proximus Lacordaire
and b.) I. n. sp. 1, line = 1.0 mm: Al = abdominal
coxal line, Ee = epipleural fold of elytron, Lap =
prosternal line anterior to procoxa, Lc = coxal line
continuous around coxa, Lnc = coxal line not
continuous around coxa, Lpm = metasternal line
posterior to mesocoxa, Mp = mental plate, Msl =
mesocoxal line, Mtl = metacoxal line, Pe = pronotal
epipleuron, P1 = procoxal line, Pps = prosternal-
pronotal epipleuron suture, Ps = prosternum, Psp =
the prosternal line in front of the procoxa or the
metasternal line behind the mesocoxa.
In the majority of Ischyrus species the coxal lines
are not connected to other lines and extend onto the
sclerite (Fig. 9a). If the coxal line is connected to the
anterior or posterior line, it is "continuous around the
coxae," because there is no break in the line surrounding
the coxae (Fig. 9), and the line does not extend onto the
The prosternum is a T-shaped sclerite with the base
between the procoxae and the cap anterior to the procoxae.
The anteromedial section of the prosternum is often keel-
like and elevated above the sides to the level between the
procoxae (Fig. 10), straight in profile. This elevation
makes the anterior margin project at the middle, appearing
as a "pitcher-like lip" (according to Boyle 1956). When
the prosternum is keeled and has this "pitcher-like lip," I
refer to it as being "pinched," because it appears
laterally pinched. The strength of this pinch, also the
amount it projects, is variable throughout Ischyrus and can
be absent (Fig. 10a, 10b), weak (Fig. 10c, 10d), or strong
(Fig. 10e, 10f).
In a few species (for example, I. n. sp. 5, I. n. sp.
6, and I. n. sp. 7) the prosternal keel appears anteriorly
swollen just behind the margin (Fig. 10g, 10h). I call
this "swollen above the pinch."
Figure 10. Prosternal development: a.) ventral and b.)
lateral view of Ischyrus aleator Boyle [Mexico,
Sonora] prothorax lacking anterior pinch, line = 0.60
mm; c.) ventral and d.) lateral view of Ischyrus q.
quadripunctatus (Olivier) [USA, Florida] prothorax
with weakly developed prosternal keel and pinch, line
= 0.60 mm; e.) ventral and f.) lateral view of
Ischyrus scutellaris Gorham [Mexico, Yucatan]
prothorax with strong keel and pinch, line = 0.40 mm;
g.) ventral and h.) lateral view of Ischyrus n. sp. 7
[Panama] prothorax with prosternal keel swollen above
pinch, line = 0.44 mm.
I use the term "prosternal plate" in reference to the
surface of the prosternum between the coxal lines (Fig. 9).
This "plate" is most often flat, but can be slightly
convex. The plate shape varies throughout the genus (Fig.
11), from semicircular (wider than long) to elongate,
parallel-sided (longer than wide).
The length of the procoxal lines varies from species
to species. I use three phrases to describe the length of
these lines in relation to the procoxae: surpassing coxae,
barely surpassing coxae, not surpassing coxae. The phrase
"surpassing coxa" (Fig. lib) indicates the line passes
beyond an imaginary line drawn between the anterior edge of
the procoxae. The phrase "barely surpassing coxa" (Fig.
lla, 11c) indicates the line passes beyond the point where
the line in front of coxa begins, but does not pass beyond
an imaginary line drawn between the anterior edge of the
procoxae. The phrase "not surpassing coxa" (Fig. lid)
indicates where the line stops where the line in front of
procoxae begins, well before the imaginary line.
Many species have sexual dimorphism on the prosternum
in one or two forms. The majority of the species studied
have a differing number, or varying development, of foveate
punctures in front of the procoxa. In these species,
females have more numerous or distinct foveate punctures
than the males (Figs. 12-14), the opposite of Delkeskamp's
(1959) observations of certain African Dacninae.
a b c d
Figure 11. Prosternal plates showing procoxal line
shapes and anterior development, line = 1.0 mm;
a.) Ischyrus proximus Lacordaire, barely
suprassing coxa; b.) I. n. sp. 7, parallel-sided
and surpassing coxa; c.) I. n. sp. 5, semicircular
and barely surpassing coxa; d.) I. duponti
Lacordaire, not surpassing coxa. Imaginary line
(dashed) included for referencing anterior edge of
procoxae in determining procoxal line development.
Figure 12. Prosternal sexual dimorphism in puncture
development. Male Ischyrus n. sp. 7 [Panama]
prosternum: a.) ventral view, line = 0.38 mm; b.)
lateral view, line = 0.50 mm; c.) ventral view of
prosternal-pronotal epipleural suture, line = 0.17 mm;
d.) prosternal punctures in front of procoxa, line =
0.04 mm. Female Ischyrus n. sp. 7 [Panama]
prosternum; e.) ventral view, line = 0.43 mm; f.)
lateral view, line = 0.50 mm; g.) prosternal punctures
in front of procoxa, line = 0.04 mm.
Figure 13. Prosternal sexual dimorphism in puncture
development and lateral expansion. Male Ischyrus
incertus Lacordaire [Mexico, Chiapas] prosternum: a.)
ventral view, line = 0.75 mm; b.) lateral view, line =
0.50 mm; c.) ventral view of laterally expanded
prosternal-pronotal epipleural suture, line = 0.17 mm.
Female Ischyrus incertus Lacordaire [Panama]
prosternum; d.) lateral view, line = 0.50 mm; e.)
ventral view of prosternal-pronotal epipleural suture,
line = 0.25 mm.
Figure 14. Prosternal sexual dimorphism in puncture
development and lateral expansion. Male Ischyrus
scutellaris Gorham [Mexico, Yucatan] prosternum: a.)
ventral view, line = 0.60 mm; b.) ventral view, line =
0.30 mm; c.) lateral view of prosternal expansion,
line = 0.12 mm. Female Ischyrus scutellaris Gorham
[Mexico, Yucatan] prosternum; d.) ventral view, line =
0.50 mm; e.) ventral view of prosternal-pronotal
epipleural suture, line = 0.17 mm.
In a few species, males have the prosternum expanded
laterally, obscuring the prosternal-pronotal epipleural
suture (Figs. 13-14). The extent of the expansion appears
consistent in all specimens of a species, but is variable
among species. It can be a small expansion (Fig. 13), or
it can nearly cover the entire pronotal epipleuron (Fig.
The mesosternum has few useful characters. The length
of the mesosternal lines in relation to the distance
between them, along with the meso-metasternal suture shape,
is useful in grouping related species. This suture can be
truncate (Fig. 15a), sinuate (Fig. 15f), or broadly sinuate
The metacoxal lines usually extend posteriorly away
from the medial side of the mesocoxa towards the hind angle
of the metasternum (Fig. 9, 15). These lines are variable
in shape and length.
Anteriorly, the metacoxal lines can stop near the
mesocoxa or continue along the meso-metasternal suture,
often meeting at the middle. The shape of the line between
the coxae varies from species to species and is useful in
grouping related species. The term recurvedd" is used to
describe a line that curves away from the meso-metasternal
suture (Fig. 15c-f). Medially, these lines can take
several forms: absent, not recurved nor meeting medially
d e f
Figure 15. Meso- and metasternum showing coxal line
development, line = 0.5 mm: a.) Ischyrus
auriculatus Lacordaire, not recurved or meeting at
middle; b.) I. aleator Boyle, not recurved and
meeting at middle; c.) I. undulatus Gorham,
recurved and meeting at middle; d.) I. n. sp. 13;
e.) I. distinguendus Lacordaire, Mc = mesocoxa, Ms
= mesosternum, Mt = metasternum; f.) I. n. sp. 3.
(Fig. 15a); not recurved meeting in a straight line (Fig.
15b); meeting with a series of punctures or undulations
(Fig. 15c); meeting as a single tooth (Fig. 15e); meeting
with two widespread teeth (Fig. 15d); or meeting with many
teeth (Fig. 15f).
The mesosternal line behind the mesocoxa is variable
in its structure from species to species. It can be a
simple line (Fig. 16a) which is single-sided, a groove
(Fig. 16b) which is double-sided, or a groove which is
notably deeper on one end and leads into a large pit (Fig.
16c). This pit is most often present at the medial end of
this line, but the groove can be deepened at the lateral
end (for example, I. n. sp. 13).
First Visible Abdominal Sternite
The coxal lines on the first visible abdominal
sternite extend posteriorly from the medial side of the
metacoxa. They are variable in length from specimen to
specimen and are of little use in determining species.
This first visible abdominal sternite can be rounded,
broadly rounded or truncate between the metacoxa at the
junction with the metasternum.
The internal sac of the male genitalia is held
inverted within the median lobe (Fig. 17a). During
copulation, the internal sac is everted, exposing any
microstructure and extending the flagellum (Fig. 17b). The
median lobe, internal sac, and flagellum are the true
Figure 16. Metasternal line posterior to mesocoxa: a.)
simple line on Ischyrus proximus Lacordaire [Mexico,
Chiapas], line = 0.75 mm; b.) groove on Ischyrus q.
quadripunctatus (Olivier) [USA, Florida] line = 0.38
mm; c.) groove with pit at medial end on Ischyrus n.
sp. 3 [Panama], line = 0.28 mm.
Figure 17. Male genitalia of Ischyrus q. quadripunctatus
(Olivier), line = 0.66 mm; a.) internal sac inverted
as held within the body; b.) internal sac and
flagellum everted as during copulation; F =
flagellum, Is = internal sac, Ma = sclerite for
muscle attachment at anterior end of flagellum, Ml =
medial lobe, Ms = median strut.
intromittent organs and show the majority of species
specific characters. For additional insight into the
genitalia of Coleoptera, I recommend the following:
Lindroth 1957; Sharp and Muir 1912; Skelley 1993; Snodgrass
1957; Tuxen 1970; Verhoeff 1895; Williams 1945; and Wood
The median lobe is a simple tubular structure that is
curved and laterally flattened. The degree of curvature
varies from species to species and can be slightly curved
to arched. The shape of the median lobe's posterior end
varies, and can be truncate, rounded, or narrowed and then
The internal sac occasionally has pigmented areas,
which are patches of microspinules. These can be large
lightly pigmented patches of widely scattered
microspinules, or small dark paired patches. These patches
are known in only a few species.
I found the shape of the sclerite for muscle
attachment at the flagellum's base to be important in
species recognition. The sclerites are all basically U-
shaped, but with many variations. Just posterior to this
sclerite is a pigmented section. This section of the
flagellum is often variable in shape and curvature. A
close study showed it to be flexible, like cartilage. The
shape of this structure was not used to distinguish species
because it can vary from specimen to specimen. The
flagellum is variable throughout the genus: long,
cylindrical, and hair-like; flattened and ribbon-like; or
straight and rigid. The tip of the flagellum can be
pointed or flared.
Female genitalia (Fig. 18) varied little from species
to species. Structures had proportions which varied, but
species recognition based on female genitalia was not
possible with any degree of confidence. The sclerotized
spermatheca showed some variation in shape which could be
useful in studies of higher categories.
The spermatheca consisted of two parts; the head and
tail. The head is the large bulbous, terminal structure,
which varies in shape from circular to kidney-shape. Many
species have spermathecae with a top-knot (bump on the
head), variable in size and occasionally in position. The
spermatheca tail is a sclerotized section of the duct
extending from the spermatheca's head to the genitalia.
The shape and thickness of the tail is variable, but
similar in related species.
Materials and Methods
Dry preserved specimens were borrowed from many
sources (institutions and individuals) during this
revision. Appendix B lists these sources with their coden
(mostly from Arnett et al., 1993) used throughout this
Figure 18. Female genitalia of Ischyrus q. quadripunctatus
(Olivier), line = 1.0 mm: a.) spermatheca; b.) ventral
view; c.) dorsal view; A9 = abdominal segment IX, H =
head of spermatheca, P1 = proctigeral lobe, S8 =
abdominal sternum VIII, sS8 = straps appendant to
abdominal sternum VIII, sT8 = straps appendant to
abdominal tergum VIII, St = styli, T8 = abdominal
tergum VIII, T = tail of spermatheca, Tk = top-knot on
In most taxonomic research the investigators must
study material seen by the describer of a species in
creating the description. These specimens are the
reference point for the name. Many descriptions were
poorly done, or lack specific details needed to identify
additional specimens. The history of each "type" specimen
becomes important in locating it or discovering if it still
exists. Modern researchers must record the depository of
specimens studied. Early researchers did not always do
this. Horn and Kahle (1935-1937) and Sachtleben (1961)
stated the location or fate of many collections and can be
helpful in locating a specific specimen.
For New World Erotylidae the majority of early type
material can be found in three places: the Museum National
d'Histoire Naturelle, Paris (MNHN); the Crotch Erotylidae
Collection, University of Cambridge, U.K. (CUMZ); and the
Natural History Museum, London (NHML).
Many of the nomina nuda in Dejean's catalogs (1836,
1837) and collection, were validated by Lacordaire because
he acquired Dejean's Erotylidae (Horn & Kahle 1935-1937)
and used Dejean's names in his descriptions. Horn & Kahle
indicate that Lacordaire's collection was divided and
deposited in various European museums. I have been unable
to find all of Lacordaire's Erotylidae, but he studied
specimens of several other collectors whose material can be
found in two places: the Crotch collection (CUMZ); or the
Oberthir collection (MNHN).
Many of Lacordaire's species were described from the
Dupont collection. Horn & Kahle indicate that the Dupont
collection was divided with some of the material being
deposited in the collections of G. V. Mniszech and R.
Oberthir. Nicole Berti at the Museum National d'Histoire
Naturelle, Paris (in litt.), stated that the Oberthur
collection, including the Mniszech collection, is at the
MNHN, and that Oberthir indicated on the back of a box that
specimens studied by Lacordaire are in the collection of
Mniszech. For Ischyrus, the specimens labeled "Type" from
this collection matched the original descriptions in both
morphology and label data. Most specimens in this
collection do not have "Type" labels, but they are
potentially type material and should be considered in
subsequent type designations for Lacordaire species.
Lacordaire also studied specimens from the collections
of L. A. A. Chevrolat and L. J. Rieche. These erotylid
collections, and others, were acquired by G. R. Crotch.
Crotch's Erotylidae collection, at the Cambridge University
Museum of Zoology, is rich in types. In this collection,
label data indicate which specimens are types, and often
from whose collection they came. The Ischyrus specimens
labeled "Type" fit the original descriptions, label data,
and collection of origin.
The Natural History Museum, London, (formerly known as
the British Museum of Natural History) houses the specimens
studied in the Biologia Centrali-Americana (Gorham 1887-
Tracking one specimen illustrates that it is not
always a simple matter. The type specimen of Ischyrus
quadripunctatus (Olivier), the generotype of Ischyrus, was
not studied by Boyle (1956) in his family revision of
America north of Mexico. Olivier (1791) stated that the
specimen was in the collection of M. Francillon. Horn and
Kahle (1935-1937) state that the Francillon collection was
divided and deposited in the Natural History Museum,
London, and the Hope Entomological Collections, University
of Oxford, U.K. I visited the Natural History Museum and
found no specimen which could be the type. The curator of
the Hope Entomological Collections, G. C. McGavin, wrote
that the majority of their part of the Francillon
collection was sent to the (Alexander) MacLeay Museum,
Sydney, Australia, in 1818. The curator of the MacLeay
Museum, D. S. Horning, Jr., wrote that they do have
specimens from the Francillon collection, including some
from the locality stated in Olivier's description. But, he
would be unable to look for the specimen until his recent
injury had healed. Thus, I still do not know if the
specimen studied by Olivier exists.
Specimens of the genus Ischyrus can be found feeding
on their host fungus. Based on the number of specimens
known for most species, we still do not know where to look.
Most specimens appear to have been haphazardly collected,
even those collected in light traps.
No definitive statement can be made about where to
look for, or how to collect, members of this genus. I have
collected various species of Ischyrus and related genera by
using a beating square on dead sticks at night. Sticks,
limbs, branches, etc., which produced the most specimens
were either still on the tree, or on the ground, but
suspended above the surface. The only known hosts are
prostrate white fungi which seem to prefer dead suspended
Much work remains to be done in understanding the
biology of this genus and the family. (See the Biology
section under the Generic Account for additional comments.)
Specimens were studied under a binocular dissection
microscope, Unitron ZSB, with a zoom-magnification of 0.7x-
4.5x and 20x ocular lenses. A Hitachi S-570 scanning
electron microscope was used. Although useful in seeing
and understanding many of the minute characters, it was not
an essential part of this study. I made an effort to base
species descriptions and key characters on those visible at
Adult specimens often needed to be cleaned before
surface structures could be studied. This was accomplished
by brushing the specimen with a small soft-bristle brush
dipped in ethyl acetate or alcohol. Ethyl acetate was also
used to degrease badly soiled specimens. If the mouthparts
were badly soiled, the specimen was dipped in warm water to
loosen the dirt, and to relax the specimen before brushing
the dirt away. On rare occasions specimens were so badly
soiled that they were totally relaxed, cleaned, and
European-style card mounting made it impossible to
study the ventral surfaces without removing the specimen
from the card. The solvent used to soften the glue
depended on what glue was used. The following series of
chemicals was used until one dissolved the glue: water, 70%
isopropanol, 80% ethanol; ethyl acetate. Rarely did the
specimen require treatment with all of these, but
occasionally a specimen needed to have the glue manually
I dissected many genitalia for further study.
Specimens were chosen from across the distributional range
of the species and from those showing variation in external
characters. Each specimen was put into a weak solution of
hot detergent water and allowed to sit from one hour to
overnight. Once relaxed, the specimen was carefully held
between the thumb and forefinger under the dissecting
microscope. With a pair of jewelers forceps, the elytra
were lifted just enough to slip one side of the forceps
underneath and the abdomen was grasped on a side. In this
way, the specimen was held and the remainder of the body
was not effected by the dissection to follow.
The abdominal tergites (membranous) and underlying
muscle masses were separated from the visible sternites on
the side not held by the forceps. This was done with a
bent-tipped minute attached to a small wooden toothpick.
Once loosened, the forceps were moved to hold only the
sternites of the side just separated, and the same
operation performed on the second side. After these
separations were complete the tergites and underlying
muscle masses were removed with a second pair of forceps.
This technique allows the visible abdominal sternites to
remain attached; the specimen appears intact.
The removed muscle masses containing the genitalia,
and terminal segments of the abdomen, were cleaned and
cleared in a warm 10% potassium hydroxide (KOH) solution,
and the remaining unwanted tissues were removed manually
with forceps. The genitalia were rinsed in 70% isopropanol
or water and stored in glycerin in genitalia vials
associated with the appropriate specimen. Genitalia vials
are small plastic or glass vials that can be placed under
the pinned specimen, with the pin piercing the stopper.
Detailed study of these genitalia rarely required more
magnification than the dissecting microscope allowed. The
genitalia were studied in glycerin, and moved into various
positions to see the shape of the muscle attachment at the
anterior end of the internal sac. The shapes of this
structure and the flagellum were important in solving many
of the species problems. When finished, the genitalia were
returned to the genitalia vial and pinned under the
The stridulatoryy files" were not studied for many
species since this required removing the head from the
body. This type of dissection destroyed the specimen, and
I was not willing to sacrifice the few specimens available
for most species.
Illustrations were made with the use of a glass-grid
insert placed in an ocular of the dissecting microscope.
The imposed grid on the specimen was used as reference and
the drawing was made on a piece of grid paper. It was
necessary to make various adjustment to each of the
drawings, because the curvature of the lenses produced
distortions. This was most apparent when comparing the
finished pencil drawing and the specimen without the aid of
the microscope. The drawings were then traced in India ink
onto tracing paper with a 000 Koh-i-nor Rapidograph
technical pen, scanned into electronic form using a Hewlett
Packard Scanjet IIP, finished using CorelDRAW* 2.01 (a
computer graphics program) on a Unisys 486 personal
computer, and printed with an Apple LaserWriter" II.
Habitus drawings lack legs and antennae for several
reasons. First, the legs are of little use in determining
species. The antennae need to be illustrated side-by-side
for close comparisons. Adding these structures doubles or
triples the time to do an illustration. Lastly, by
omitting these structures, the habitus drawings can be
placed closer together, requiring less space and fewer
In plotting distribution maps, many specific
localities were not found because of poor label data. If
the information was adequate enough find the general area,
an open symbol was placed on the map in the general area.
Specific localities are shown with solid symbols. If label
data were vague and there was already a plotted locality in
the general area, an additional symbol was not added.
Questionable records are plotted with a question mark "?".
Color Pattern Problems
Species level decisions have historically been based
simply on color and color patterns. Museum specimens vary
in the shades of orange because of age, killing agent, and
preservation technique. Because of this, the exact color
is of little use in species determination.
The color pattern is most important in determining
species, but care must be taken in analyzing differences.
The specimen(s) in question must first be placed within the
proper section of the genus. This was done by using
morphological and genitalic characters. Many recently
described species were compared to an unrelated species in
the original description. This made determinations based
on the literature impossible, and the type specimens had to
A different appearing color pattern did not
necessarily mean the specimen was a different species. For
example, a species may have two spots on each elytron.
When these spots are enlarged, they blend together and form
a band. Differences based on changes in pattern due to the
spot size generally were not specific.
In other cases, a spot which varied in its location,
generally indicated a specific difference. For example, in
two closely related species the only color pattern
difference is that one species has a humeral spot touching
the base and the other has a subhumeral spot well removed
from the base. In I. scriptus, I. proximus, I. palliatus,
and I. incertus, the relative position of the pronotal
spots and the shape of the circle they form is useful in
Written descriptions cannot convey the exact details
of these patterns the way an illustration does. Every
species and many variations are here illustrated. In some
cases the differences are subtle, but they are constant and
correlate with other morphological differences. Care
should be taken when comparing any specimen to these
illustrations because of color pattern variations mentioned
above, and ones not yet known.
Studying series of specimens from a large geographic
range has allowed me to observe geographic variations in
color patterns that were once considered specific. One
such character is the color of the head, which can be red,
black, or with some variation of both. In only a few
cases has this variation been more than a clinal or
The term "pattern" was used for variations of a color
pattern in situations where previously described species
were found to be part of a dine. These "patterns" were
maintained because they still had some relation to a
geographic range. The "pattern" name is the specific name
that once applied to that pattern, or a name was applied
if that "pattern" was not previously described. New
"pattern" names were applied only if specific names already
existed for other patterns (see I. quadripunctatus and I.
scriptus). These named "patterns" have no nomenclatural
Another general trend is the change of elytral
patterns from north to south. Many species have solid
bands with smooth edges in the north; moving south, these
edges become more and more sinuate. Some even develop into
stripes as the sinuate edges on both sides of the band
meet. Many species from mid-South America have striped
patterns. In contrast, the majority of northern species
have banded patterns. This is best illustrated with I.
quadripunctatus, I. scriptus, and their variations. This
trend may indicate mimetic relationships among species.
Rules of Thumb
In determining the taxonomic status of various names,
and in naming new taxa, several general rules were followed
which require some explanation.
Many species are variable in color pattern over their
geographic range. This is illustrated in several species
where adequate series have been studied. Certain color
patterns are known from only a few specimens, often from
scattered localities. If two specimens have different, but
basically similar color patterns and their morphology
(including the genitalia) is similar, they are considered
variations of a single species.
In other cases a radical color pattern difference is
observed, but the genitalia are incomparable (i.e., male
vs. female). These are considered variations of a single
species, and are discussed under the most closely related
described species, noting the variations and their
If a previously described species was a member of
several patterns in a dine, that name was synonymized
under the senior name and discussed in the species account.
Consistent morphological differences correlated with
color pattern differences are considered to be specific,
and these taxa are described. New species are simply
numbered, because of problems with nomeclatural priority,
and names will be proposed when published.
The lack of series in many species indicates that
there is much to be discovered in this genus. Several of
the species discussed here may actually represent
complexes. Because of inadequate material these problem
taxa are left unresolved and are discussed under the
appropriate species account.
The genus Ischyrus is composed of 42 North and Central
American species, including 16 previously undescribed;
leaving 30 additional described species in South America.
A total of 3741 North and Central American specimens was
studied (2890 I. quadripunctatus) and 363 were dissected.
The 148 figures, key, appendices, and descriptions are
provided to complete this revision.
Ischyrus Lacordaire 1842:89-131.
Micrischyrus Alvarenga 1965:86.
Type Species. Erotylus quadripunctatus Olivier
1791:431,437. Subsequent designation by Crotch
Diagnosis. Characterized by having coarsely faceted
eyes, triangular mentum, short ocular stria not surpassing
anterior angle of eye, undilated tibia, and semicircular or
trapezoidal antennomere IX.
Description. Length 3.5 9.9 mm. Body shape
parallel-sided, to elongate, or ovoid, slightly flattened to
convex dorsally; microreticulation, surface dull to shining;
unicolorous brown to variously banded or spotted, yellow-
orange with black pattern.
Head with ocular striae generally ending at or before
anterior angle of eye, rarely extending onto epistome at
base of antenna; frons often with an impression at each side
near base of antennae; epistome wedge-shaped, generally with
truncate apex; epistome punctures generally denser than
punctures on vertex. Eye large, bulging from side; facets
coarse (Fig. la), varying in size throughout the genus,
Antenna surpassing middle of pronotum, often reaching
basal 0.25; antennomere I large, elongate; antennomere II
circular, ball-like, length = 0.5 x antennomere I;
antennomere III elongate, length equal to next 2 to 4
segments combined; antennomeres IV to VIII length subequal
to width, length rarely more than 1.5 x width; antennomeres
IV to VII rounded at ends; antennomere VIII edged and angled
apically; antennomeres IX to XI form a loose club;
antennomeres IX to X 3 to 4 x wider and 1.5 to 2 x longer
than antennomere VIII; antennomere IX semicircular to
trapezoidal, rarely triangular (Fig. 6); antennomere X
crescent-shaped to trapezoidal; antennomere XI transversely
elongate-oval to circular; antennomeres X-XI often
Mandibles each with two finger-like teeth and a large
prostheca bearing many inwardly pointing setae. Maxilla
with lacinia bearing an apical tooth, often bifid (Fig.
19b); terminal segment of palp triangular or securiform,
width = 1 to 3 x length. Labial palpi vary from squared or
circular to securiform, width = 1 to 2 x length (Fig. 7).
Mentum with a pore on each side in front of basal corner;
mental plate triangular, rarely longer than wide; ridge
surrounding plate often raised laterally giving mentum a
three prong crown-shape, medial prong (medial ridge
extension) variously shaped, protruding or not (Figs. 8,
19a). Postmandibular lobes present, broadly rounded,
Figure 19. Ischyrus q. quadripunctatus (Olivier)
a.) labium and b.) left maxilla ventral
view, line = 0.25 mm: M = mentum, Lp =
labial palp, Mp = maxillary palp, T = bifid
tooth of lacinia.
Figure 20. Ventral view Ischyrus q. quadripunctatus
(Olivier) [USA, Florida] head and prosternum, line =
forming inner side of groove next to the eye for reception
of antennomeres II to III (Fig. 20).
Pronotal disc evenly rounded; sides variably arched
inwardly toward eyes; anterior angles closer together than
posterior angles; anterior edge not margined between eyes;
anterior angles forwardly produced, making anterior edge
concave; base sinuate, not margined, lobed at middle, with
group of large punctures at each side. Scutellum
pentagonal, wider than long.
Elytra with sides parabolically rounded to apex; 7 to 9
stria evident by rows of punctures, lacking at humerus and
extreme apex, rarely impressed or missing; intervals
flattened, often with minute punctures; base rarely
margined; elytral epipleuron widest at base, strongly
narrowed at hind coxae, gradually folding under to apex
(Fig. 9); some elytral punctures each with a small
protruding seta, visible in profile.
Prosternum usually keeled, margined and constricted
(pinched) at front (Figs. 10, 20); sternal plate shape and
proportions variable (Fig. 11); lines anteriorly converging
or parallel, rarely surpassing front of procoxa, lines not
continuous around coxae (except n. sp. 1); posteriorly
prosternum truncate or slightly concave, not margined.
Mesosternal lines parallel or anteriorly divergent,
straight or arched; plate square or transversely
rectangular; posteriorly sinuate or truncate.
Metasternal lines extending onto disc from inside of
mesocoxa toward posterior angle of metasternum, rarely
continuous around mesocoxae; variable in length, up to 0.5
distance to posterior angle; line behind mesocoxae variably
impressed or grooved, occasionally with pit (Fig. 16).
Legs with femora slightly swollen, complete margin on
inner surface (Fig. 21); tibia straight, almost parallel-
sided, slightly widened toward apex; tarsi
Abdominal coxal lines present, short; rarely continuous
Male genitalia with median strut length variable, equal
to or larger than median lobe; internal sac can bear patches
of spinules; flagellum varying in length and thickness, with
sclerotized muscle attachment at base, non-slerotized
section at base flexible; lateral lobes of tegmen generally
Female genitalia with straps appendant to abdominal
segment VIII; abdominal segment IX elastic, length variable;
flattened plate-like proctigeral lobe; apical segment of
coxite with slender styli (Fig. 18). Proportions of these
stuctures vary little throughout the genus. Spermatheca
sclerotized, shape of head and tail variable, occasionally
with a top-knot (Fig. 18).
Stridulatory files often present at the base of the
head (Fig. 22).
Figure 21. Ventral view of meso-femur: a.) Ischyrus q.
quadripunctatus (Olivier) [USA, Florida] with posterior
margin, line = 0.50 mm; b.) Oocyanus flavitarsis
(Lacordaire) [Cuba] lacking posterior margin, line =
Figure 22. Ischyrus q. quadripunctatus (Olivier) [USA,
Florida] occipital region of head showing stridulatory
file (arrow): male with stridulatory file, a.) line =
0.38 mm, b.) line = 0.08 mm; c.) female lacking
stridulatory file, line = 0.15 mm.
Sexual dimorphism often present. Males of some species
have the prosternum laterally expanded onto the pronotal
epipleuron; not expanded in females (Figs. 13-14). Males of
many species have fewer, or less distinct, punctures on the
prosternum in front of the procoxae (Figs. 12-14).
Distribution. This genus is restricted to the New
World, where it is widespread, occurring from southeastern
Canada near the St. Lawrence Seaway and southeastern North
Dakota through the eastern U.S. and southern Arizona,
Mexico, Central America, the West Indies, into South America
to northern Argentina.
Bioloav. The life history of this genus is basically
unknown. Only one species has its larva described; the type
species I. q. quadripunctatus (Olivier) (see Weiss 1920,
Skelley 1988b, Chapuis & Candeze 1855, Chapuis 1876). The
following is based on published accounts of this species, a
few bits of information taken from label data, and personal
communications and observations.
The larva of I. q. quadripunctatus has well developed
dorsal sclerotization with short spines. It is unusual in
that the pronotal sclerotized area is broken into parts
appearing like false eyes (Fig. 23). Members of a related
genus, Oocyanus Hope, have a similar set of "eye-spots".
This peculiarity could be of adaptive significance in
warding off predators. Both of these larvae have been found
feeding exposed on prostrate white fungus growing on dead
wood (personal observations). Other larvae of the
Figure 23. Ischyrus q. quadripunctatus (Olivier) larva
[USA, Florida], line = 4.0 mm.; a.) lateral view; b.)
dorsal view of head and thorax.
Erotylidae are burrowers in fungi (some Triplacinae,
Dacninae) or are surface feeders (some Erotylinae). The
surface feeding Erotylinae are often protected by a covering
of large spines and often have color patterns; whereas
burrowing species lack these spines and patterns (see
Roberts 1958; Costa, et al. 1988; and Lawrence 1991, for
illustrations of various erotylid larvae).
Ischyrus q. quadripunctatus has been collected on a
white resupinate polypore fungus, Oxyporus latemarginatus
(Dur. & Mont. ex. Mont.) Donk, also known as Poria ambigua
Bres. (Skelley, et al. 1991). Richard Leschen (pers. comm.)
collected I. proximus on Schizopora paradoxa (Fr.) Donk in
Costa Rica, also a white resupinate polypore. Both of these
fungi are white rot fungi of wood.
Adults have been taken by general collecting methods;
in leaf litter, under bark, sweeping vegetation, etc. Many
specimens have been taken at light, suggesting nocturnal
activity. This is also indicated by the large eye facets
present in members of this genus. Using a beating square at
night, I collected several species of Ischyrus and other
related genera on small dead limbs both on the ground and
hanging from the trees.
Several species have pits on one of the thoracic
sternites, for example; I. undulatus and I. n. sp. 3 on the
metasternum behind the mesocoxa, and I. n. sp. 1 on the
prosternum. These pits occur on both sexes of the species
and show no sexual dimorphism in their development. Their
function is not known, but they could be used for structural
support, muscle attachment, areas for glandular secretion,
or mycangia (Crowson 1981).
Etymoloav. Ischyros: Greek for strong, mighty,
excessive (Brown 1985). Possibly named in reference to the
strongly clubbed antennae or pronounced color patterns.
Gemminger and Harold (1876) indicated that the name Ischyrus
Remarks. Although Boyle (1956:110) stated that
Ischyrus lacks teeth on the lacinia; this is incorrect. The
tooth illustrated (Fig. 19) is located in a dense patch of
setae and is difficult to see.
Ischyrus Lacordaire appears most closely related to
Megischyrus Crotch, Callischyrus Crotch, and Oocyanus Hope
in having a triangular mentum, loose antennal club,
strongly microreticulate body surface, and in basic color
Ischyrus differs from Oocyanus in having the femora
margined along the inner side where the tibiae meet the
femora (Fig. 21a); this margin is lacking in Oocyanus (Fig.
21b). Callischyrus differs from Ischyrus in having the eyes
finely faceted and the ocular stria surpassing the antennal
base; in Ischyrus the eyes are coarsely faceted and the
ocular stria at most touch the antennal base. Megischyrus
differs from Ischyrus in having a larger body size (greater
than 11 mm) and in having antennomere IX triangular (Figs.
6n-o); in Ischyrus the body size is smaller (less than 10
mm) and antennomere IX is semicircular or trapezoidal,
References. Alvarenga 1965:85; Arnett 1963:817-821;
1985:341-342; Blackwelder 1945:465; Boyle 1956:132-137,128;
Chapuis 1876:35-38; Crotch 1873a:353-354; 1873b:144;
1876:426-433(50-57); Curran 1944:1-5; Edwards 1949:94;
Gemminger & Harold 1876:3690-3691; Germar 1843:133; Girard
1873:820; Gorham 1887:39-45; Kuhnt 1909:55,57,61-64;
1911:42-44; Lacordaire 1842:89-131; LeConte & Horn 1883:124;
Leschen 1991:180, 192; Mader 1942:171,195-196; 1951:209-210;
Neave 1939-1940:790; Pallister 1955a:4; 1955b:6-7; Seidlitz
1891:288; Skelley 1988b:60.
ARTIFICIAL KEY TO SPECIES
This key was built using characters visible under low
magnification, without dissection. Several species appear
in the key more than once, beacuse some characters are
variable or have an intermediate state on some species.
Couplet 3 is the best example of a character that can be
difficult to interpret. If a specimens does not adequately
key, or does not match what it does key to, then try the
other choice in the couplet.
1. Antennomere IX triangular, sides straight, as long or
longer than wide (Figs. 6k, 6n-o); body convex dorsally
(Fig. 2b) ........................................... 2
1'. Antennomere IX trapezoidal to semicircular, sides angled
or rounded, generally wider than long (Figs. 6a-j, 61-
m); body parallel-sided, elongate or ovoid; flattened
above (Fig. 2) ...................................... 3
2.(1) Pronotum with 2 free spots (Fig. 24). .
.............................. vespertilio Lacordaire
2'. Pronotum with central stripe (Fig. 25). ..... n. sp. 1
3.(1') Antennal club segments distinctly asymmetrical;
antennomere XI larger (wider or longer) than
antennomere X (Fig. 6a-f) ........................... 4
3'. Antennal club segments symmetrical; antennomere XI size
variable; if appearing asymmetrical, antennomere XI
24L 25 26 27
28 29 30 31
32 33 34 35
Figures 24-35. Dorsal habitus, line = 1.0 mm: 24.)
Ischyrus vespertilio Lacordaire; 25.) I. n. sp. 1;
26.) I. n. sp. 2; 27.) I. distinguendus Lacordaire;
28.) I. insolens Crotch; 29.) I. scriptus (Olivier)
"northern"; 30-31.) I. scriptus "southern"; 32.) I.
bogotae Crotch; 33.) I. incertus Lacordaire; 34.) I.
proximus Lacordaire; 35.) I. angularis Lacordaire.
equal in size or smaller than antennomere X (Fig. 6g-
m). .............................................. 19
4.(3) Pronotum without free spots ........................ 5
4'. Pronotum with free spots ............................. 6
5.(4) Pronotum with a central black stripe and red sides, no
basal spots (Fig. 26). ................... n. sp. 2
5'. Pronotum red with three basal spots only (Fig. 27). .
............................ distinguendus Lacordaire
6.(4') Pronotal hind angles with a dark marking, black of
lateral margin encroaches upon the side ............. 7
6'. Pronotal hind angles without distinct dark markings .. 8
7.(6) Pronotum with 4 free spots in a transverse arc; 2
central spots well separated from the base (Fig. 28). .
..................................... insolens Crotch
7'. Pronotum with 2 basal, 2 central, and 2 anterior spots
forming a circle; 2 central spots close to or connected
with the base (Figs. 29-31) ...... scriptus (Olivier)
8.(6') Pronotum with 2 free spots; 2 basal spots rarely free
or weakly touching margin; if appearing free, then
spots separated from base by less than their diameter
(Figs. 29, 32-35). .................................. 9
8'. Pronotum with 3-4 free spots; if 4, then central spots
separated from base by more than their diameter (Figs.
37-47). .. .......................................... 14
9.(8) Pronotum with spots on anterior margin. ......... 10
9'. Pronotum without spots on anterior margin ......... 13
Figures 36-47. Dorsal habitus, line = 1.0 mm: 36.) Ischyrus
septemsignatus Gorham; 37.) I. tripunctatus Crotch;
38.) I. frontalis Lacordaire; 39.) I. frontalis var.;
40.) I. dunedinensis Blatchley; 41.) I. boucardi
Crotch; 42.) I. quadripunctatus chiasticus Boyle; 43-
47.) I. quadripunctatus quadripunctatus (Olivier); 43.)
I. q. q. "quadripunctatus"; 44.) I. q. q. graphicsus;
45.) I. q. q. "subcyindricus"; 46.) I. q. q.
"Antillean"; 47.) I. q. q. "banded-leg".
10.(9) Pronotum with 1 large basal spot (Fig. 32). .
...................................... bogotae Crotch
10'. Pronotum with 2 basal spots ........................ 11
11.(10') Antennomere XI equal in size to antennomere X (Fig.
61); femur black; elytra with weak microreticulation,
strongly shining; pronotal spots forming a transversely
elongate ellipse (Fig. 33) ........ incertus Lacordaire
11'. Antennomere XI larger than antennomere X (Fig. 6c);
femur red or black; elytra with dulling
microreticulations; pronotal spots forming a circle,
longitudinally elongate circle, or rarely a weak
transverse ellipse (Figs. 29-31, 34) ............... 12
12.(11') Femur red with dark knee; humeral spot free from
scutellar spot; elytral epipleural fold black,
occasionally pale in general specimens; pronotal spots
form a circle or weakly transversely elongate ellipse
(Figs. 29-31) ..................... scriptus (Olivier)
12'. Femur and scutellum black; humeral spot connected to
scutellar spot; elytral epipleural fold red, at least
at base, rarely dark; pronotal spots forming a
longitudinally elongate ellipse (Fig. 34)..............
................................. proximus Lacordaire
13.(9') Elytra with central band and apical spots connected
to suture (Fig. 35) .............. angularis Lacordaire
13'. Elytra with central band and apical spots not reaching
the edge (Fig. 36) .............. septemsignatus Gorham
14.(8') Pronotum with 3 free spots ..................... 15
14'. Pronotum with 4 free spots ........ ................. 17
15.(14) Central elytral band broken into spots .......... 16
15'. Central elytral band complete (Fig. 37) .
.. ............................ tripunctatus Crotch
16.(15) Lateral spot of elytra small, circular; Central
America (Figs. 38-39). ......... frontalis Lacordaire
16'. Lateral spot of elytra elongate, stripe-like; USA,
Florida (Fig. 40). dunedinensis Blatchley
17.(14') Maxillary palps narrow (Fig. 7f), longer than wide.
...................... quadripunctatus (Olivier). .18
17'. Maxillary palps wide (Fig. 7c), wider than long; (Fig.
41) ................................... boucardi Crotch
18.(17) Scutellar spots form an X-shaped mark; narrow band
of black at base of pronotum (Fig. 42) .
................... quadripunctatus chiasticus Boyle
18'. Scutellar spots not X-shaped, or if X-shaped then base
of pronotum with prominent tooth-like spots (Figs. 43-
47) ....... quadripunctatus quadripunctatus (Olivier)
19.(3') Metasternal line behind mesocoxa impressed with a
distinct pit near middle (Figs. 15c, 15f, 16c);
epistome angled at side, flat and sharp in profile;
face flat, usually lacking impressions; body
cylindrical ................. ...... ................. 20
19'. Metasternal line behind mesocoxa without pit, often
impressed (Figs. 15a-b, 15d-e, 16a-b); epistome angled
or not, often thickened at apex and rounded in profile;
face often with impressions; body often flattened .. 21
20.(19) Pronotum with 2 basal spots and a central stripe
connecting the base and anterior margin (Fig. 48). .
........................................ n. sp 3
20'. Pronotum without a central stripe, 4 free spots (Fig.
49). ................................. undulatus Gorham
21.(19') Color pattern lacking, uniformly colored, often
paler at lateral margins. ........................ 22
21'. With distinct color pattern ........................ 25
22.(21) Body with metallic blue sheen; strial punctures
present only at base and along sutural margin; Cuba
(Fig. 50) ...................... ............. n. sp. 4
22'. Body without metallic sheen; strial punctures present
over entire elytral disc ........................... 23
23.(22') Prosternum 2-3 times longer than the distance
between the procoxae (Fig. 11b); labial palps not
expanded, squared or rounded (Fig. 7k) ............. 24
23'. Prosternum at most 1.5 times longer than the distance
between the procoxae; labial palps expanded, securiform
(Fig. 7j); (Fig. 51) .......................... n. sp. 5
24.(23) Pronotal punctures distinctly larger laterally;
shiny black; parabolically rounded at sides (Fig. 52)
............................................ n sp 6
24'. Pronotal punctures same size throughout; dull brown;
parallel-sided (Fig. 53). .................... n. sp. 7
25.(21') Pronotum without free spots .................... 26
25'. Pronotum with free spots .......................... 32
56 57 58 59
Figures 48-59. Dorsal habitus, line = 1.0 mm: 48.)
Ischyrus n. sp. 3; 49.) I. undulatus Gorham; 50.) I.
n. sp. 4; 51.) I. n. sp. 5; 52.) I. n. sp. 6; 53.) I.
n. sp. 7; 54.) I. aleator Boyle; 55.) I. n. sp. 8;
56.) I. auriculatus Lacordaire; 57.) I. auriculatus
var.; 58.) I. ephippiatus Gorham; 59.) I. n. sp. 9.
26.(25) Prosternum not strongly constricted at anterior
margin, not produced in profile, not pinched (Fig.
10a). ............................................ 27
26'. Prosternum strongly constricted at anterior margin,
produced in profile, pinched (Fig. 10c-f). ......... 30
27.(26) Each elytron with 1 central stripe-like spot (Fig.
54) ..................................... aleator Boyle
27'. Elytra banded or spotted ........................... 28
28.(27') Pronotum entirely pale, elytra with small spots
(Fig. 55) .................................... n. sp. 8
28'. Pronotum black or with black markings, elytral marking
variable. ......................................... 29
29.(28') Elytra with distinct free spots, not banded (Fig.
25); metasternal coxal lines continuous behind
mesocoxae; line behind mesocoxa not impressed;
prosternal line in front of coxa a pit-like groove
(Fig. 9b) .................................... n. sp. 1
29'. Elytra distinctly banded (Figs. 56-57); metasternal
coxal lines not continuous behind mesocoxae, long; line
behind mesocoxa impressed, groove-like; prosternal line
in front of coxa simply impressed. . .
.............................. auriculatus Lacordaire
30.(26') Body stout, rounded laterally; pronotum entirely
black, or with anterior angles pale; each elytron with
a free basal spot .................................. 31
30'. Body parallel-sided, elongate; pronotum with pale
anterior angles and often with central red markings;
elytra lacking free basal spots (Fig. 58) .
.................................. ephippiatus Gorham
31.(30) Free scutellar and humeral spots in transverse line,
central elytral fascia not extended to apical quarter
(Fig. 59) ............................... n. sp. 9
31'. Free humeral spot located behind free scutellar spot;
central elytral fascia reaching apical quarter (Fig.
60) ......................................... n. sp 10
32.(25') Pronotum with 2 free spots and three basal spots (1
band-like free spot in collatinus), 3 basal spots not
including possible posterior angle spots ........... 33
32'. Pronotum with 2 or more free spots, possibly with three
basal spots, but not with the above combination .... 37
33.(32) Pronotal hind angle with a spot or widening in the
black margin; often with 2 weak black spots at anterior
margin of pronotum (Fig. 61) ................ n. sp. 11
33'. Pronotal hind angle without spot, lacking spots at
pronotal anterior margin ........................... 34
34.(33') Two free pronotal spots circular; scutellar spot
often broadly connected to elytral base ............ 35
34'. Free pronotal spot(s) transversely elongate,
rectangular; scutellar spot not connected to elytral
base ............................................... 36
35.(34) Apical elytral spot free; central band not reaching
lateral margin (Figs. 62-63) ............ pictus Gorham
35'. Apical elytral spot broadly connected to suture and
apex; central band complete, reaching lateral margin
(Fig. 35) ................ angularis Lacordaire
60 61 62 63
S 64 65 66 67
68 69 70 71
Figures 60-71. Dorsal habitus, line = 1.0 mm: 60.) Ischyrus
n. sp. 10; 61.) I. n. sp. 11; 62.) I. pictus Gorham;
63.) I. pictus var.; 64.) I. episcaphulinus Gorham;
65.) I. collatinus Crotch; 66.) I. elegantulus
Lacordaire; 67.) I. elegantulus var.; 68.) I. chacojae
Gorham; 69.) I. chacojae var.; 70.) I. scutellaris
Gorham; 71.) I. scutellaris var.
36.(34') Pronotum with 2 free rectangular spots; lacking
sutural spot near elytral apex (Fig. 64) .
............................... episcaphulinus Gorham
36'. Pronotum with 1 transverse spot; with a sutural spot
near the elytral apex (Fig. 65) ..... collatinus Crotch
37.(32') Pronotum with 2 free spots, base at most with thin
black margin, rarely with anterior spots ........... 38
37'. Pronotum variously marked with 2-4 discal spots, other
markings variously connected to margins ............ 42
38.(37) Scutellar spot narrowly connected to elytral base at
scutellum, connection narrower than the spots' width
(Figs. 66-67). ................. elegantulus Lacordaire
38'. Scutellar spot broadly connected to elytral base,
connection same width as spot ...................... 39
39.(38') Humeral and scutellar spots usually separated;
scutellar spot broadly connected to suture; antennomere
IX rounded or angled at base, not triangular ....... 40
39'. Humeral and scutellar spots connected, appearing as
one, separated from suture; antennomere IX triangular
(Fig. 24). ... .................. vespertilio Lacordaire
40.(39) Head entirely red; humeral spot not connected to
elytral base ....................................... 41
40'. Head with at least base black; humeral spot connected
to elytral base, often connected to scutellar spot
(Figs. 68-69). ....................... chacojae Gorham
41.(40) Central elytral band broken into round spots (Figs.
70-71) ............................. scutellaris Gorham
41'. Central elytral band broken into longitudinally
elongate spots (Fig. 72) .................... n. sp. 12
42.(37') Pronotum with 3 free spots ..................... 43
42'. Pronotum with 2 or 4 free spots .................... 45
43.(42) Central elytral fascia complete (Fig. 37) .
................................. tripunctatus Crotch
43'. Central elytral fascia broken into spots. ........ 44
44.(43') Lateral spot of elytra small, circular; Central
America (Figs. 38-39) ............ frontalis Lacordaire
44'. Lateral spot of elytra elongate, stripe-like; USA,
Florida (Fig. 40). ............. dunedinensis Blatchley
45.(42') Pronotum with 2 free, 2 basal, and 2 anterior spots
(Fig. 33). ........................ incertus Lacordaire
45'. Pronotum with 4 free spots; or with pronotal disc
markings based on 4 spots in a transverse line; 2
central spots occasionally connected to the anterior
margin, giving it the appearance of 2 free spots ... 46
46.(45') Pronotum with 4 free spots only; occasionally with
dark base, but no distinct basal spots ............. 47
46'. Pronotum with 4 free spots and additional markings
connected to margins ................................ 48
47.(46) Elytral central spot not connected to suture (Fig.
73) .......................... ............... n. sp. 13
47'. Elytral central band complete, one continuous marking
connected to suture, possibly reaching lateral margin
(Fig. 74) ......................... tetrasticus Gorham
Figures 72-78. Dorsal habitus, line = 1.0 mm: 72.)
Ischyrus n. sp. 12; 73.) I. n. sp. 13; 74.) I.
tetrasticus Gorham; 75.) I. n. sp. 14; 76.) I. n. sp.
15; 77.) I. fulmineus Delkeskamp; 78.) I. n. sp. 16.
eS 5 4
48.(46') With distinct anterior pronotal markings, or
markings connecting discal spots to anterior margin 49
48'. Without distinct anterior pronotal marks, discal spots
free (Fig. 75) .............................. n. sp. 14
49.(48) Each pronotal hind angle with a spot, occasionally
reduced and appearing as dark swelling at margin of
disc ............................................... 50
49'. Pronotal hind angles without spots, lateral margin dark
but not extending onto disc (Fig. 76) ....... n. sp. 15
50.(49) Humeral spot connected to elytral base; central
elytral band divided by orange except at stria V & VI
(Fig. 77). .................... fulmineus Delkeskamp
50'. Subhumeral spot not connected to elytral base; central
elytral band completely divided by orange (Fig. 78). .
....................................... n. sp 16
Ischyrus aleator Boyle
Ischyrus aleator Boyle 1954:46-48.
Diagnosis. Unique in Ischyrus by its linear elytral
spots (from base at humerus to apical third), pronotum
lacking free spots, and weakly pinched prosternum.
Description. Length: 5.6-7.4 mm; Width: 2.5-3.4 mm.
Body elongate, parallel-sided, widest at basal third elytra;
strongly microreticulate, dull; pale orange with black
pattern (Fig. 54).
Head orange, often with black epistome. Pronotum
entirely edged in black; anterior edge with 2 spots; basal
edge with 2 spots farther apart than anterior spots; spots
occasionally touching on disc. Scutellum black. Each
elytron with black epipleural fold, often with pale base;
suture finely edged in black; disc with elongate triangular
stripe, widest anteriorly, narrowly connected at base near
humerus, reaching apical quarter of elytra. Ventral color
variable from mostly black to orange with black sclerite
edges. Legs black, femur occasionally banded with pale
Head dorsal distance between eyes = 2.3 x eye width;
ocular striae reaching antennal base; vertex and epistome
puncture size = 1 x facet, separated on vertex by 2
diameters, separated on epistome by 1 diameter. Antenna
reaching base of pronotum; antennomere III as long as next 3
antennomeres combined; antennomeres IX-XI symmetrical;
antennomere XI oval, circular to transverse (similar to Fig.
Maxillary palp terminal segment semicircular; medial
edge straight at base, angle 90; lateral side rounded,
angle obtuse; width = length. Labial palp terminal segment
triangular, extended on medial side, narrow, sides rounded,
width = 0.8 x length. Labial palp width = 0.5 x maxillary
palp width (Fig. 7m). Mentum with plate broadly triangular,
length = 0.5 x width, sides slightly convex, ridge medial
extension acutely pointed (Fig. 8i)
Pronotal disc puncture size = 1 x facet, separated by 2
to 3 diameters; lateral punctures slightly larger and
denser, separated by 1 to 2 diameters. Scutellum
pentagonal, length = 0.6 x width. Each elytron with 7
visible striae; strial puncture size = 0.5 x lateral
pronotal puncture size, becoming finer toward apex;
intervals finely punctate, obscured by strong
Prosternum not keeled, convex; anterior pinch weak, if
present (Fig. 10a-b); with (female) or without (male)
foveate punctures in front of procoxa; coxal lines nearly
straight, length = 0.5 x sternal length, lines not
surpassing coxae, length = 0.6 x basal width; prosternal
plate flat, apical width = 0.75 x basal width; base
Mesosternum basal width = 2 x mesocoxal line length;
coxal lines straight, parallel to anteriorly divergent; base
sinuate. Metasternum coxal lines meeting at middle in
straight line with a row of punctures, often weak (Fig.
15b); coxal line length variable, continuous around coxae or
reaching a maximum of 0.33 distance to posterior angle of
metasternum; line behind mesocoxa deep, groove-like; sternum
medial punctures fine, few coarse lateral punctures.
First visible abdominal sternite with coxal lines
reaching 0.25 to 0.5 distance to posterior margin; rounded
Male genitalia with median lobe weakly arched, narrowed
and apically rounded; internal sac without noticeable
sclerotized structures; flagellum long and narrow, straight
and apparently rigid at basal 0.5, length = 2 x median lobe
length (Fig. 79a); base of flagellum straight, sclerite at
base elongate claw-shaped (Fig. 79b-d) (9 northern Mexican,
1 Central American dissected).
Female genitalia with spermathecal head cone-shaped;
tail swollen and recurved onto itself at middle (Fig. 79e)
(6 northern Mexican dissected).
Stridulatory files present on occipital region of
males' heads; absent on females. Males with few or no
foveate punctures on prosternum in front of procoxae;
females with few to many punctures on prosternum in front of
e79 d 9"
a ---- -
Figures 79-83. Genitalia: 79.) Ischyrus aleator Boyle
[male, Mexico, Chihuahua; female, Mexico, Sonora];
80.) I. angularis Lacordaire [male & female, Panama];
81.) I. auriculatus Lacordaire [male, Mexico, Chiapas;
female, Mexico, Veracruz]; 82.) I. bogotae Crotch
[male, Costa Rica, Puntarenas; female, Ecuador,
Pichincha]; 83.) I. boucardi Crotch [male, Panama;
female Peru, Madre de Dios]; a.) male genitalia, line
= 0.66 mm; b.) lateral view, c.) dorsal view, and d.)
anterior view of the sclerotized muscle attachment at
anterior end of male flagellum, line = 0.22 mm; e.)
female spermatheca, line = 0.33 mm.
procoxae. There is some overlap in the numbers of visible
punctures between males and females.
Variation. Markings vary dramatically in the width on
specimens from north to south. Pronotal markings often
touch in the middle, becoming stripe-like, leaving 3 pale
circles. The width of the elytral stripe varies from 1 to 3
strial intervals. Central American specimens have banded
legs, an orange elytral epipleural fold, and black epistome.
Specimens from Northern Mexico and Arizona have entirely
black legs, black epipleural fold, and an orange epistome.
The type specimen, which appears to be slightly general, has
Variation in mesocoxal line, from parallel to
anteriorly divergent, did not correlate with geographic
range. Specimens from Arizona and northern Mexico have the
metacoxal line short, reaching a quarter of the distance to
the posterior angle, or continuous around the coxae.
Specimens from southern Mexico and Central America have the
metacoxal lines longer, nearly reaching a third of the
distance to the posterior angle.
The prosternal pinch is not present on the holotype.
On other specimens this pinch varies from absent to weak but
Type. The holotype (original designation) of Ischyrus
aleator Boyle label data: "/ Cave Creek, Cochise Co./
Chiricahua Mts., AZ., 7000ft, June 24, 1927/ J.A.Kusche
Collector/ Van Dyke Collection/ [red] Holotype Ischyrus
aleator Boyle/" [CASC, Type #8369, studied]. Sex male.
Specimens examined. The holotype and 44 specimens,
representing 20 collection records, were studied (see
Appendix C for specific data).
Distribution. Southeastern Arizona, Mexico, El
Salvador, and Guatemala (Fig. 84).
Etymology. aleator: Latin = dice layer, gambler. Name
alludes to the resemblence of the trifoliate tawny spot on
the pronotum to the emblem of the club suit in a deck of
cards (Boyle 1954).
Taxonomic notes. The variation in leg color, size of
elytral stripe, and development of metacoxal lines, appear
to be correlated with geographic range. Few specimens with
banded legs were studied from central Mexico and Central
America. The importance of this color variety is uncertain.
References. Boyle 1956:133,136-137,169 f.131-132;
Skelley et al. 1991:65.
Ischyrus angularis Lacordaire
Ischyrus angularis Lacordaire 1842:126
Ischyrus quinquepunctatus Gorham 1887:43-44, t.3 f.6,
Diagnosis. Characterized by its elongate body,
complete central elytral band, apical elytral spots touching
margins, and 2 free and 3 basal pronotal spots.
Description. Length: 5.0-5.8 mm; Width: 2.4-2.9 mm.
Body elongate, parallel-sided, widest at basal third of
Figure 84. Ischyrus aleator Boyle [circle]
and I. angularis Lacordaire [star]
elytra; weakly microreticulate, shining; yellow-orange with
black pattern (Fig. 35).
Head entirely black, or with orange epistome and frons.
Pronotum with 2 free spots and 3 basal spots; medial basal
spot small; lateral basal spots larger, tooth-like.
Scutellum black. Each elytron with orange epipleural fold;
elongate subhumeral spot connected to base, often narrowly
connected to large scutellar spot at base; scutellar spot
broadly connected to base and suture; suture finely edged
black; central band connected to lateral margin and suture;
apical spot broadly connected to suture and apical margin;
lateral margin black from central band to apex. Venter
black, except for the orange lateral abdominal sternites and
pronotal epipleuron. Legs black, tarsi brown.
Head dorsal distance between eyes = 2.2 x eye width;
ocular striae reaching 0.8 to 1.0 distance to anterior angle
of eye; vertex puncture size = 1 x facet, separated by 1 to
2 diameters; epistome puncture size = 0.5 x facet, separated
by 1 diameter. Antenna reaching basal 0.25 of pronotum;
antennomere III as long as next 3 antennomere combined;
antennomeres X to XI asymmetrical; antennomere XI transverse
Maxillary palp terminal segment triangular, securiform,
basally rounded, apical angles nearly 900, length = 0.75 x
width. Labial palp terminal segment triangular, extended on
medial side, rounded basally, length = 0.66 x width. Labial
palp width = 0.75 x maxillary palp width (similar to Fig.
7b). Mentum with plate broadly triangular, length = 0.6 x
width, sides straight, ridge medial extension acutely
pointed (similar to Fig. 8d).
Pronotal puncture size = 1 x facet, separated by 1 to 2
diameters; punctures smaller and denser at extreme lateral
edge. Scutellum pentagonal, length = 0.75 x width. Each
elytron with 7 complete striae; stria VIII weak, visible on
apical half; strial puncture size = 2 x pronotal disc
punctures, gradually decreasing in size posteriorly;
intervals finely punctate.
Prosternum keeled and pinched anteriorly; with (female)
or without (male) foveate punctures in front of procoxa;
coxal lines straight, length = 0.5 x sternal length, lines
surpassing coxae, length = basal width; prosternal plate
flat, apical width = 0.6 x basal width; base shallowly
Mesosternum basal width = 2.5 x mesocoxal line length;
coxal lines straight; base sinuate, lobed medially.
Metasternum coxal lines not meeting at middle; coxal lines
extend 0.5 distance to posterior lateral angle; sternum with
medial punctures fine, few coarse lateral punctures
separated by 2 to 3 diameters.
First visible abdominal sternite with coxal lines
reaching 0.5 distance to posterior edge; rounded between
metacoxae; coarse punctures laterally, fine punctures
Male genitalia with median lobe weakly arched, apically
truncate with constriction just before tip; internal sac
with end near median lobe roughened; flagellum long and
narrow, length = 1.6 x median lobe length (Fig. 80a); base
of flagellum straight, sclerite at base claw-shaped (Fig.
80b-d) (2 dissected).
Female genitalia with spermathecal head kidney-shaped,
often with top-knot; tail swollen, weakly curved (Fig. 80e)
Presence of stridulatory files on occipital region of
head unknown (heads retracted). Females have foveate
punctures on prosternum in front of procoxae; males lack
Variation. One specimen with a red head, probably
general, has the same collection data as a black headed
Types. The lectotype (here designated) of Ischyrus
angularis Lacordaire label data: "/ Colombie/ Angularis
Lac./ Type/ Ex-Musaeo Mniszech/ [red] TYPE/ [pale blue]
Museum Paris ex Coll. R. Oberthiir 1952/ [red] LECTOTYPE
Ischyrus angularis Lacordaire des.P.E.Skelley 1993/" [MNHN,
studied]. Sex apparently female, abdomen missing.
The holotype (by monotypy) of Ischyrus quinquepunctatus
Gorham label data: "/ [red circle on white paper] Type/ Type
sp. figured/ Bugaba, Panama, Champion/ Ischyrus 5-punctatus
Gorham/ B.C.A., Col.,VII, Ischyrus/" [NHML, studied]. Sex