Official Organ of the Florida Entomological Society
VOL. XXIII OCTOBER, 1940 No. 3
BAETINE MAYFLIES FROM FLORIDA
Since Nathan Banks described Callibaetis floridanus from
Biscayne Bay in South Florida forty years ago (1900), no addi-
tional species of Baetinae have been reported from the state.
Even Banks' species has been mentioned only once in the litera-
ture, when it was redescribed by Traver in "The Biology of
Mayflies" in 1935. During the past three years, I have been
studying the Ephemeroptera of Florida, and in the course of
this work have found at least fifteen additional species of Bae-
tinae, representing seven genera (including Calibaetis); three
of the species are undescribed. Among the sixteen species of
this subfamily, six are represented only by nymphs or by nymphs
and females, both forms of limited taxonomic value, and because
of the uncertainty in identification, such species will not be
treated here. The present contribution includes the records and
descriptions of those identified Baetine species which are now
definitely known to occur in Florida; their ecological distribution
will be discussed in a later paper.
The lack of flowing water in South-central and Southeast
Florida has kept all lenitic forms out of this region, and here
Callibaetis floridanus is the only representative of the Baetinae.
Northwest Florida, on the other hand, has numerous, moderately
flowing streams in which nymphs of all of the forms described
in this paper can be found.
Rearing has been carried out entirely in the laboratory. A
small stream of air forced into an aquarium proved to be quite
effective for keeping mature, stream-inhabiting, Baetine nymphs
alive for several days and allowing many of them to emerge,
an act which they seem to perform with difficulty in quiet water.
However, some of the species occur in regions from which it is
impossible to transport such intolerant nymphs and consequently,
1Contribution from the Department of Biology, University of Florida.
Pseudocloeon alachua, abdomen of nymph. Fig. i
Pseudocloeon alachua, fourth gill. Fig. :
Pseudocloeon alachua, seventh gill. Fig.
Pseudocloeon alachua, labial palp of Fig. :
nymph. Fig. :
Baetis spiethi, abdomen of nymph.
Baetis spiethi, fourth gill. Fig. :
Baetis spiethi, sixth gill.
Baetis spiethi, labial palp of nymph. Fig.:
Baetis spiethi, seventh gill. Fig. :
Baetis spinosus, abdomen of nymph.
Baetis spinosus, labial palp of nymph.
Baetis spinosus, fourth gill.
Baetis spinosus, seventh gill.
Acentrella ephippiatus, abdomen of
Acentrella ephippiatus, labial palp of
Acentrella ephippiatus, seventh gill.
Acentrella ephippiatus, fourth gill.
Centroptilium viridocularis, first gill. Fig. 26.
Centroptilium viridocularis, fourth gill.
Centroptilium viridocularis, seventh gill. Fig. 27.
Callibaetis floridanus, maxilla of nymph. Fig. 28.
Callibaetis floridanus, seventh gill.
Centroptilium viridocularis, labial palp of Fig. 29.
nymph. Fig. 30.
Pseudocloeon alachua, genitalia of male
imago. Fig. 31.
Callibaetis floridanus, genitalia of male
imago. Fig. 32.
Centroptilium viridocularis, genitalia of
Baetis spiethi, genitalia of male imago.
Acentrella propinquus, genitalia of male
Baetis spiethi, hind wing of male imago.
Centroptilium viridocularis, hind wing of
Acentrella propinquus, hind wing of male
Callibaetis floridanus, hind wing of male
THE FLORIDA ENTOMOLOGIST
in these instances, the association of adult and nymph has had
to be inferred.
I have followed Ide's method of describing immatures, in
which the description is not based on a single specimen but on
the average of a number of specimens.
I wish to express my appreciation to Professor T. H. Hub-
bell, Department of Biology, University of Florida, for critizing
the manuscript, to Dr. H. H. Hobbs, of the same department,
for valuable suggestions concerning drawings, and to friends
who have collected numerous mayflies for me. In recording
locality records of Florida materials examined, the name of the
collector is placed in parentheses along with the date of the
collection; records without such names are my own.
Callibaetis floridanus Banks
MALE IMAGO (in alcohol):
Measurements: Length of body-5.3-7.0 mm.; fore wing-4.7-6.5 mm.;
caudal filaments-9.9-12.6 mm.
Head: Light brown; anterior margin of frontal shelf red-brown, re-
mainder whitish-hyaline suffused with brown; median carina white; vertex
dark brown between compound eyes. Base of ocelli brown, distal portion
white; brown dash under lateral ocelli; brown markings extending from
anterior border of each lateral ocellus almost to dorso-proximal margin of
median ocellus. Turbinate portion of compound eyes orange dorsally,
remainder yellowish-white except for dark-brown line at base on medial
side; lower portion of eye black. Basal segment of antenna white ventrally,
dusky dorsally, distal margin red; second segment whitish ventrally, dor-
sally brown; flagellum brownish becoming pale distally. Ventral surface
of head yellowish-white.
Thorax: Brown marked with tan; freckled with brown (a very small
seta arising from each spot). Median line of pronotum light tan; entire
pronotum bordered by dark brown line; submedian tan patch on posterior
border. Mesonotum predominantly light brown; median line reddish; an-
terior border with thin dark brown line; submedian brown stripes bounded
laterally by tan stripe; lateral and posterior portions of scutum dark
brown; face of ridge at posterior border of scutum yellowish-white, this
followed by brown; scutellum tan, posterior border dark brown. Metanotum
dark brown; mid-portion of anterior margin dark brown, midportion of
posterior border tan. Pleura brownish marked with yellow; large brown
areas anterior to each coxa; yellow stripe extending downward from root
of mesothoracic wing. Prosternum yellowish-white; brown border on an-
terior and posterior margins, also brown line on medial side of each coxa.
Mesosternum yellow marked with brown; anterolateral portion brown,
medial part yellow; posterolateral regions brown; dark brown border on
posterior and anterior margins and also around coxae. Metasternum pre-
dominantly yellowish-brown; brownish in anterior portion, white between
coxae, dark brown along caudal border.
VOL. XXIII-No. 3 37
Wings: Hyaline, veins not colored; mesothoracic wings with stigmatic
areas whitish; this whitish area extending through costal border; inter-
calaries double near tip of wing, single along outer margin; twenty to
twenty-five cross-veins posterior to R1. Several cross-veins of metathoracic
wings incomplete (fig. 32).
Legs: Coxa marked with brown; femur with obsolescent reddish spots
arranged longitudinally on outer side; trochanter, tibia, and tarsus white.
Claws brown, blunt claw whitish at tip.
Abdomen: Freckled with obsolescent brownish spots (a very small seta
arising from each spot). Tergite 1 brown in mid-region, laterally yellowish-
brown; 2-6 hyaline whitish; posterior margin in mid-region reddish;
faint brownish submedian areas on posterior half of tergites 2-6; 7-10
predominantly brownish; anterior portion of 7 semi-hyaline; longitudinal
whitish patches on 7-10; 7 and 8 light brown; 9 and 10 dark brown. Dark-
brown, lateral streaks on tergites 1-9 in region of spiracles; reddish-brown
streak just below this on sternites 2-9. Sternites 1-6 semi-hyaline with
suggestion of brown along mid-portion of posterior border; 7 semi-hyaline
along anterior border, predominantly white, reddish along posterior border.
Sternites 8 and 9 white, red area on mid-region of posterior border.
Genitalia: White; terminal forceps segment short, expanded distally
Caudal filaments: White, unmarked.
Variations: Femora with reddish spots absent; tarsal joining brown.
Brownish tinge in wings; veins yellow. Tergite 1 entirely brown; tergites
2-7 with faint, median, longitudinal stripe extending onto anterior half
of tergite 8; tergites 7-10 mostly brown. Sternites 2-9 with blackish spot
at mid-anterior margin, these spots fainter on 8 and 9; a pair of sub-
median brown dashes near anterior margin of sternites 2-9; reddish streaks
absent from sternites. Caudal filaments with faint brown annulations at
NYMPH (in alcohol):
The nymphs of C. floridanus are distinguished from the other
Florida species by the relatively long second segment of the
maxillary palp and by the absence of a flap on the seventh gill
(figs. 21, 22).
Measurements: Length of body-5.8-8.7 mm.; length of caudal fila-
Head: Yellowish-brown; upper portion of compound eyes orange-brown,
lower portion black. Lateral ocelli tan, medial side of base dark brown;
middle ocellus brownish; dark brown basal area on dorsal side. Antennae
yellowish. Segments of maxillary palp subequal.
Thorax: Brown with tan markings. Median area of pronotum tan,
lateral to this, a triangular brown area with base along anterior margin;
this triangle followed by broad yellowish area; a large brown spot in
center of triangle; remainder of pronotum mostly brown. Meso- and
metanotum brown. Pleura brown. Sternum yellowish-brown.
Legs: Yellowish-brown, marked with darker brown. Coxa yellowish,
brownish on outer side; trochanter yellowish, tinged with brown; femur
yellowish-brown, brown band near distal end; tibia, tarsus, and tarsal claw
THE FLORIDA ENTOMOLOGIST
yellowish-brown. Tibia and tarsus brown at their distal margins. Setae
on legs brown.
Abdomen: Tergites predominantly brown. Tergite 1 mostly yellowish-
brown; posterolateral margins brown; tergites 1-9 with faint submedian
dashes at anterior margins; 7 and 8 with brown dashes in anteromedial
region; 2-8 with yellowish, longitudinal lines extending length of tergites
just medial to gills; anterolateral and posterolateral margins of tergites
2-9 pale, these pale areas separated by brown bar. Sternites yellowish,
usually unmarked; if marked, brown triangle at mid-posterior margin of
sternites 1-9 with base along posterior margin; apex of triangle extends
to about middle of sternite; the base of triangle may spread out on caudal
sternites and form a rather broad, brown, posterior band. In strongly
marked specimens, there may be longitudinal brown dashes near lateral
margins on sternites 1-9. Posterolateral spines on segments 6-9 about
equal in size. Inconspicuous brownish spots (a very small seta arising
from each spot) irregularly scattered over abdomen. Gills brownish-
hyaline; gills 1 and 2 four lobed, 3-6 double and 7 single; tracheae promi-
Caudal filaments: Yellowish-brown. Hairs yellowish-brown; in region
of long hairs, filaments sometimes brownish but usually not different in
color from remainder of tail. Spines at joints prominent, brown; at base
of tails, prominent brown spines on every second segment; distally, to end
of region of long hairs, spines occurring on every fourth segment, produc-
ing an annulate effect. Segments with the prominent spines usually
brownish. Beyond region of long hairs, tails yellowish-brown.
Locality records: Alachua Co., general in Gainesville area
(numerous records of adults and nymphs from April, 1937-
March, 1940); Citrus Co., near Withlacoochee River (nymphs,
March 25, 1938) ; Collier Co., Pinecrest (adults and nymphs,
August, 1937); Columbia Co., Lake City (nymphs, May 12,
1937) ; Dade Co., Royal Palm State Park (adults, July 31, 1937),
Pinecrest (adults, August 3, 1937), generally around Miami area
(adults and nymphs, July-November, 1937); Gilchrist Co., Su-
wannee River (adult, April 5, 1938); Highlands Co., Child's
Crossing (adults, August 11, 1938, T. H. Hubbell), Highlands
Hammock State Park (nymphs, May 13, 1939, F. N. Young);
Hillsborough Co., Tampa (nymphs, April, 1937 and 1938), Six-
Mile Creek (nymphs, March, 1938), Little Fish-hawk Creek
(nymphs, March, 1938) ; Jackson Co., Blue Springs Creek
(adults, July 1, 1939) ; Lake Co., St. Johns River at Crow's Bluff
(adult, September 12, 1938, J. R. Preer) ; Lee Co., Bonita
Springs (nymphs, February 8, 1939, A. F. Carr) ; Levy Co.,
6 miles N. E. Cedar Keys (nymphs April 9, 1937), Otter Creek
(nymphs April 9, 1937), 4 miles S. Bronson (nymphs, November
14, 1937, H. H. Hobbs); Marion Co., Juniper Springs (nymphs,
November 21, 1937), Oklawaha River at Eureka (nymphs, Feb-
VOL. XXIII-No. 3
ruary 12, 1938), Withlacoochee River (nymphs, March 25,
1938) ; Monroe Co., Pinecrest (adults, July, 1935, and December,
1937, F. N. Young; August 24, 1937), Turner's River (nymphs,
December 25, 1935, F. N. Young) ; St. Johns Co., near Trout
Creek (nymphs, April 23, 1938, F. N. Young) ; Sumter Co., 1
mile N. Sumter Co. line (nymphs, March 27, 1938) ; Taylor Co.,
Perry (nymphs, April 1, 1938, H. H. Hobbs; February 5, 1938) ;
Volusia Co., Benson Springs (adults, August 30, 1938, J. R.
Preer) ; Polk Co., Polk-Lake Co. line (nymphs, May 13, 1939,
F. N. Young) ; Putnam Co., Welaka (adults, December 29, 1938;
July 5, 1939, A. M. Laessle).
Centroptilium viridocularis n. sp.
DIAGNOSIS: Abdominal tergites 2-6 of male imago semi-
hyaline, yellowish-white; 7-10 ochraceous; width of metathoracic
wing equal to one-fourth length; process of hind wing only
slightly hooked; penis cover broadly truncate; distal forceps
segment small, curved. (Figs. 26, 30.)
RELATIONSHIPS: On the basis of a combination of characters
(mesothoracic color, red markings on tergites 2-6, color of ter-
gites 7-10, and presence or absence of a projection on inner
margin of second forceps segment), Centroptilium viridocularis
is distinct from other described species. Comparison of Traver's
drawings of the metathoracic wings (1935) of some species of
Centroptilium with those of C. viridocularis leads me to asso-
ciate the latter with C. convexum, C. conturbatum, or C. rufostri-
gatum. However, on the basis of Traver's drawings of genitalia,
the relationships would seem to lie with C. rufostrigatum or C.
fragile. Since both wings and genitalia are similar to those of
C. rufostrigatum, these two species may possibly be the most
DESCRIPTION OF HOLOTYPIC MALE IMAGO (in alcohol):
Measurements: Length of body-4.1 mm.; length of wing-3.7 mm.;
length of caudal filaments-6.3 mm.
Head: White; reddish-brown mark where anteromedial angle of tur-
binate eye meets head; brown, submedian dash near base of antenna. Tur-
binate eyes large, oval, contiguous at base. When viewed from above,
eyes completely cover pronotum and anterior portion of mesonotum. Upper
portion of turbinate eyes greenish-yellow; a brown line around rim; basal
portion grayish-brown; discontinuous dark-brown line separating the
grayish-brown from upper greenish portion. Lower part of eye dark gray.
Ocelli ringed with dark brown at base. Basal segments of antennae white,
tinged with brown; flagellum dusky except at tip.
Official Organ of the Florida Entomological Society
VOL. XXIII OCTOBER, 1940 No. 3
J. R. WATSON, Gainesville----...................-- ............................Editor
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Issued once every three months. Free to all members of the
Subscription price to non-members is $1.00 per year in ad-
vance; 35 cents per copy.
Thorax: Pronotum brownish. Mesonotum grayish-yellow marked with
white and brown; anterolateral borders white; a pair of brownish, sub-
median lines divergent anteriorly, fusing posteriorly; just lateral to these
lines, in mid-region, a pair of white spots; posterior portion of scutum
tinged with brown, scutellum brown. Metanotum dark-brown in anterior
half, caudally yellowish-brown. Pleura white; sternum pale yellow.
Wings: Hyaline. Stigmatic area of fore wing granulate; no inter-
calaries in first interspace; four stigmatic cross-veins. Metathoracic wing
process only slightly hooked; longitudinal veins two, no cross-veins; four
times as long as wide.
Legs: White; claws dusky. Second left leg missing from holotype.
Abdomen: Tergites 2-6 semi-hyaline, yellowish-white; 7-10 ochraceous.
Tergite 1 brownish. A red, transverse line along posterior border of
tergites 2-8 becoming obsolescent in mid-region and extending to about
midway between mid-dorsal and spiracular line. Reddish area at middle
of intersegmental membranes of segments 2-6. Tergites 3 and 6 with
light reddish, lateral areas; tergite 4 with very large, brown, lateral areas
extending from spiracular line more than half-way to mid-dorsal line;
2 and 5 with faint indications of reddish, lateral areas; 5 and 6 have very
faint reddish, submedian spots posteriorly; 7 hyaline in anterior portion,
brown in middle, and ochraceous in posterior region. Sternites 2-6 yel-
lowish-white; 7-9 white; reddish shading at anterior margin of 9; red,
transverse line on intersegmental membrane of segments 5-9 extending
almost to lateral border. Spiracular line black.
Caudal filaments: White, unmarked.
Variation: Measurements of paratypes-body length 4.1-5.0 mm.; wing
length-4.2-4.9 mm.; caudal filaments-7.5 mm. Turbinate eyes without
brown rim. Markings at bases of antennae absent. No white markings
on thorax; brown less extensive. Reddish, lateral areas on abdominal
tergites more extensive; posterior sternites with reddish tinge. No inter-
calaries in first or second interspaces; five or six stigmatic cross-veins.
VOL. XXIII-No. 3 41
DESCRIPTION OF ALLOTYPIC FEMALE (in alcohol):
Measurements: Length of body-4.5 mm.; length of wing-5.1 mm.;
length of caudal filaments-6.8 mm.
Head: Yellow; red-brown lines midway between compound eyes and
median line; submedian, brown streak just medial to antennal base. Basal
antennal segments yellow with reddish tinge; flagellum dusky.
Thorax: Pronotum brown at middle; paler near lateral margins; a
pair of white spots at posterior margin and a pair at lateral border.
Mesonotum grayish-yellow with white, lateral borders; caudal portion of
scutum white; scutellum white on posterior margin. Metanotum brown.
Wings: As in male.
Legs: As in male.
Abdomen: Red lateral and posterior markings as in male. Tergites
brownish-yellow; tergites 7 and 8 mostly light brown. Small, submedian,
red dashes on 2 and 3 at middle of segment. Sternite 9 white, 8 with
flecks of white. Tracheae prominent.
Caudal filaments: Yellowish-white.
DESCRIPTION OF NYMPH (in alcohol):
The nymphs of C. viridocularis occur in the slowly flowing
portions of creeks in vegetation and leaf drift.
Measurements: Length of body-4.4-4.8 mm.; length of caudal fila-
Head: Pale brown; two pairs of submedian, brown spots on vertex;
genae brownish; large, blackish-brown spot on outer margin of mandible;
brown spot at ventrolateral corner of lateral ocellus. Turbinate portion
of eyes slightly paler than head. Ocelli ringed with blackish-brown at
base. Basal segments of antennae pale, tinged with brown; flagellum
yellowish-white; antennae extend to posterior margin of second abdominal
segment. Distal segment of labial palp dilated, broad (fig. 23).
Thorax: Pronotum grayish-brown; a dark-brown, longitudinal line
mid-way between median line and lateral border ending at posterior margin
in a dark-brown spot. Mesonotum grayish-brown; median line yellowish-
white, enlarged at anterior margin and also just anterior to scutellum; on
either side of anterior enlargement of median line, a dark-brown spot;
on either side of posterior enlargement, a short, brown bar; at middle of
mesonotum a pair of dark-brown spots; small area at base of wing pads
and scutellum slightly paler than ground color of mesonotum. Metanotum
brown; basal part of hind-wing pad brown; outer portion yellowish. Pleura
dark brown. Sternum pale except for dark-brown area around bases of
Legs: Brownish-yellow. Middle coxa with faint, brown spot on outer
side; spot prominent on hind coxa, enlarged to cover most of outer surface;
femur with an indefinite, brown band in distal third; tip of knee dark
brown; tibia brown in mid-region; in upper-half of tibiae, on outer sides,
a pale, U-shaped ridge superficially appearing to be an additional joint.
Tarsus brownish basally becoming paler distally. Claws brown at base,
distal half lighter brown; long, thin, almost three-fourths as long as tarsi.
Abdomen: Light brown; tergites slightly paler in anterior portion,
darker posterior portion forms a large indistinct triangle with its base
along posterior margin. On tergites 3 and 6, a dark-brown, longitudinal
THE FLORIDA ENTOMOLOGIST
band at inner margin of gills extending length of segment; running laterally
from the middle of this bar, another bar which reaches to the lateral border;
on 2, 4, 5, and 7 a brown area corresponding to the transverse bar on 3
and 6. A blackish-brown, median line on tergite 1, extending almost to
posterior border; on 6, a large blackish-brown spot at middle; anterior
border of 8 narrowly blackish-brown. Intersegmental membranes of seg-
ments 6-9 with blackish-brown transverse band. Sternites pale; anterior
margins of 2-6 light brown, of 7-9 blackish-brown, this transverse band
becoming wider on 8 and 9. On 2-7, a large lateral blackish-brown spot
becoming quite large and elongated transversely on 8 and 9. Spines on
lateral margins of segments 4-10. Gills single on all segments; straight
along outer margin; tracheae prominent, branches mostly on inner side;
gill 1 reddish-brown at base (figs. 18, 19, 20).
Caudal filaments: Yellow, annulate with brown. Outermost portions
brown becoming paler at tip.
Holotype-male imago, in alcohol. Alachua Co., Hatchet
Creek (June 24, 1939). In collection of Museum of Comparative
Allotype-female imago, in alcohol. Alachua Co., Hatchet
Creek (May 6, 1939). In collection of Museum of Comparative
Paratypes-2 males, 1 female; 1 male in collection of Mu-
seum of Comparative Zoology, others in author's collection.
Alachua Co., Santa Fe River (1 male, February 28, 1939),
Hatchet Creek (1 male, July 9, 1938; 1 female, May 6, 1939).
Locality records: Alachua Co., Hatchet Creek (nymphs, May,
1938; adults, July, 1938; adults, April, May, and June, 1939),
Santa Fe River at Poe Springs (nymphs, May 21, 1934, J. S.
Rogers; adults, February, and nymphs, March, 1939), 1 mile
W. Newnan's Lake (nymphs, August 13, 1938); Gilchrist Co.,
Suwannee River (nymphs, March 4, 1939); Hillsborough Co.,
Six-Mile Creek (nymphs, March 26, 1938) ; Jackson Co., Blue
Springs Creek (adults, July 1, 1939); Leon Co., Ward (nymphs,
June 5, 1938) ; Walton Co., Ebro (adults, June 7, 1938).
The genus Acentrella Bengtsson was resurrected by Traver
in 1937 for the reception of species removed from Baetis on the
basis of the following characteristics: adult without costal pro-
jection of metathoracic wings and possessing a penis cover,
nymph two-tailed. I have found two species in Florida which
on the basis of adult characters should be assigned to Acentrella.
However, the first of these, A. ephippiatus, has three-tailed
nymphs. The other is the species which I have tentatively
identified as A. propinquus (Walsh). Whatever the identity
VOL. XXIII-No. 3
of this species, it is very probable that it also possesses a three-
tailed nymph. Clemens (1915) associated a three-tailed nymph
with the species which he (perhaps incorrectly) regarded as
that of Walsh, and it is almost certain that nymphs of the Flor-
ida form are represented in my large series of uncorrelated
nymphs, all of which are three-tailed. In fact, I have never
taken any two-tailed nymph except that of Pseudocloeon in
On the basis of the above observations, it seems rather doubt-
ful whether Acentrella is worthy of generic status, but pending
further investigation of the problem, it is here retained as a
In corresponding with Dr. Traver concerning the status
of Acentrella, she says, "Certainly, though, if some of the species
in what I have called the 'propinquus group' of Baetis (Biology
of Mayflies) have three tails as nymphs, whilst others have but
two, it does not seem that the three-ness or two-ness of tails
(that alone) should give them the rank of genus. There is, in
addition, the difference in genitalia,-presence of penis-plate,
etc.-and the lack of costal projection on hind wing. Do these
two minor differences constitute grounds for a generic differ-
ence? . .There is likely to be much shifting of generic as
well as specific names in this group [Baetinae] for some time
to come, I think, and many opinions for and against. . All
told, I am at present inclined to let the genus Acentrella remain
with us as such, until we have more proof."
Acentrella propinquus (Walsh)
In my collection, there is a series of seven males from Blue
Springs Creek, near Marianna and one from the Santa Fe River
which I am referring to A. propinquus. These specimens differ
from Traver's (1935) description in that the head, thorax and
terminal abdominal segments are paler than described (pre-
served in alcohol) ; all legs are white, unmarked; the spiracles
have black circles around them but these are broken anteriorly
and posteriorly; the wings are slightly smaller than the measure-
ments given for this species (3.9 mm.) ; hind wings are 0.51 mm.
in length, slightly over three times as long as wide. I am in-
cluding camera lucida drawings of the hind wing and of the
genitalia (figs. 28, 31).
Locality records: Alachua Co., Santa Fe River at Poe Springs
(adult, October 25, 1939); Jackson Co., Blue Springs Creek
(adult, July 1, 1939).
THE FLORIDA ENTOMOLOGIST
Acentrella ephippiatus (Traver)
I have three males of this species, all in poor condition, which
correspond well with Traver's (1935) description; two others
have much less extensive dorsal markings on pale tergites. This
species has been reared only once, but since the adults have
been taken at a creek in which three species of Baetis (or Baetis-
like) nymphs occur, two of which have been frequently reared,
it seems almost certain that the nymph I am describing is the
immature of A. ephippiatus.
The nymphs, inhabitants of vegetation in moderately flow-
ing creeks, are easily distinguished from other species of this
genus and Baetis by the combination of the three-tailed condi-
tion, reddish coloration of the gills on segments one and seven,
prominent red-brown tergites of segments 2, 5, and 8, and the
reddish markings on the venter.
NYMPH (in alcohol):
Measurements: Length of body-4.0-4.9 mm.; length of caudal fila-
ments-2.2-2.7 mm. (fig. 14).
Head: Yellowish-brown; brown spot at mid-posterior margin. Tur-
binate eyes orange. Two basal antennal segments brownish; flagellum
long and thin; yellowish.
Thorax: Dorsally light brown; irregularly marked with yellowish-
brown. Mesothoracic wing pads pale brown. Metathorax with submedian,
brownish areas; medial to base of wing pad, a red-brown spot; brownish
area at anterolateral margin. Ventrally light brown. Red-brown spots at
mid-posterior margins of meso- and metasterna. Pleura yellowish-brown;
anterior to base of third leg, a rectangular brown area. Second segment
of labial palp expanded (fig. 15).
Legs: Yellowish; coxa and trochanter unmarked; femur with incom-
plete band about two-thirds distant from proximal end on outer side;
incomplete distal femoral band; faint tibial and tarsal bands; claws yel-
Abdomen: Predominantly yellowish-brown. Tergites 2, 5, 8 reddish-
brown; others yellowish-brown. Some specimens with two pairs of sub-
median, pale spots on 2-9; on anterior segments, the anterior spot may be
prolonged into a diagonal line; pale spot along mid-line at posterior margin
of tergites 2-9; a red-brown spot on mid-line near anterior margin of
tergites 2-9; just beneath inner margin of gills on tergites 2-8 reddish-
brown line running diagonally outwards but indistinct on darker tergites;
these lines are prominent anteriorly and gradually fade out toward posterior
margin of segment. Posterolateral corner of all segments except 9 brown.
Dorsum of segment 2 mostly brown except along anterior and lateral mar-
gins; the pale, anterior margin dipping into the reddish-brown area, form-
ing two submedian V-shaped, pale blotches; these V-shaped areas confluent
with the submedian pale lines. Tergite 5 red-brown with thin, anterior,
pale margin and wide, lateral, pale margins; tergite 8 brown, pale mark-
ings as on 5 but less extensive on the anterior border. Venter yellowish-
VOL. XXIII-No. 3
brown; sternite 1 pale reddish-brown; large red-brown, transverse area at
posterior margins of sternites 2-5; this red-brown area covering mid-
posterior portion of these sternites; sternite 8 entirely red-brown. Gills
hyaline. Gills 1 and 7 mostly red-brown, clear along margins, blending
very well with tergites 2 and 8. Other gills clear; tracheae distinct (figs.
Caudal filaments: Long; yellowish with prominent, brown band at
middle; in this brown area, segments stand out clearly; bands on outer
filaments include six segments; on middle filament, eight segments; distal
portion of tails brown.
Locality records: Alachua Co., Hatchet Creek (adult, April
2, 1938; adult, March 22 and June 24, nymphs, September 14
and October 11, 1938) ; Bay Co., 25 miles N. Panama City
(nymphs, June 6, 1938), 28 miles N. Panama City (nymphs,
June 6, 1938) ; Columbia Co., Falling Creek (nymphs, June 30,
1939); Jackson Co., Altha (nymphs, July 1, 1939); Okaloosa
Co., Niceville (nymphs, June 7, 1938) ; Walton Co., 7 miles W.
Ebro (nymphs, June 7, 1938), 16 miles W. Ebro (nymphs,
June 7, 1938), 14 miles W. Freeport (nymphs and adult, June
(To be continued)
A PROBABLE COLOR DIMORPHISM IN
(Hymenoptera, Sphecidae, Sphecinae)
By H. T. FERNALD, Winter Park, Florida
This insect was first described by Say (Insects of Louisiana,
p. 14, 1832) from Louisiana. Cresson, not recognizing Say's
species, described a specimen he received from Texas and noting
its resemblance to his Sphex lautum called it a variety and at
the end of his description of lautum wrote: "Should the variety
with black abdomen prove to be a distinct species, it may be
Structurally the females of Chlorion lautum and habenum
are alike, the difference being in the color of the abdomen. In
lautum this is near cinnamon as shown in Ridgeway's "Color
Standards", while in habenum it is jet black. No males of either
lautum or habenum having a' black abdomen are known.
THE FLORIDA ENTOMOLOGIST
At the time my paper on this group of insects was published
(Proc. U. S. Nat. Mus., 31, 1906) only four specimens of
habenum were known, all females, taken in Texas, Mississippi
and Alta Mira, Tamaulipas, Mexico. Since then others have
been taken in Alabama, Honduras and twelve from College
Station, Galveston, Hunt Co., Brazos Co., Hopkins Co., and
Burleson Co., Texas, but with no males in the lot. Prof. R. W.
Strandtman, who took the Texas specimens, writes me that he
has often taken lautum at the same times, places and on the same
plants with habenum, but all were males, which would suggest
that the cinnamon-colored males of lautum are the males of
habenum. The fact cinnamon-colored females of lautum do
occur, though rarely, however, forces the belief that this species
has females with the cinnamon abdomen in some cases and
black in others.
The cinnamon-colored abdomen in the females, to judge from
the few examples whose locality is known, occur in the northern
part of the range of this insect and suggests the idea that this
color of the abdomen in both sexes remains unchanged every-
where in the males, while further south the color in the females
If this should prove correct it will involve a change of names
and the species would then be known as Chlorion (Ammobia)
habenum (Say), replacing lautum which would be applicable
to the cinnamon-colored female only, as the designation of the
cinnamon-colored variety of the female sex.
Aug. 22, 1940
Since the above was sent to the editor of this journal further
evidence to support the view there taken has been obtained. On
August 17th, 1940, while collecting on Goldenrod blossoms a
male of this species with a cinnamon-colored abdomen was cap-
tured and about 15 minutes later a female with completely black
abdomen was taken at the same place; the male being definitely
what has been called lautum and the female, habenum.
On reviewing my notes on specimens of female lautum
studied heretofore, I find that some, at least, of the females with
cinnamon-colored abdomen show dark shades, particularly below.
This would suggest that even in these specimens a tendency
toward black is present.