BULLETIN OF THE ALLYN MUSEUM
THE ALLYN MUSEUM OF ENTOMOLOGY
Number 12 26 July 1973
NEW FOODPLANT AND DISTRIBUTION
RECORDS FOR MEGATHYMUS URSUS
Ronald S.1, Dale and Joseph R. Wielgus 2
3434 West Augusta Avenue, Phoenix, Arizona 85021
On 18 November 1972, while collecting larvae of Megathymus coloradensis
arizonae Tinkham near the type locality south of Mountain View, Pima County,
Arizona, the first two authors found five larvae of Megathymus ursus ursus Poling
feeding in Yucca thornberi McKelvey. Three of the larvae were found in one yucca
clone about twenty feet south of the Old Sonoita Road, approximately 3/4 mile east
of State Highway 83, another was found in an extremely small plant situated among
two others harboring arizonae larvae, and another ursus larve was found in a
medium-sized plant farther south downslope which was partially shaded by mature
yuccas. All of the larvae were field-inspected after it became apparent that the bur-
rows of the first three larvae were unpowdered. Sunlight was used to illuminate
the larvae in the bottoms of their burrows, and the ursus larvae were immediately
distinguishable from those of arizonae. At the time of year that this collection was
made, tents of both taxa were similar except for the presence of fresh frass at the
apices of the ursus tents.
A review of the literature and personal communication with Mssrs. Don B.
Stallings and Lloyd M. Martin indicated the Y. thornberi is an heretofore unrecorded
larval foodplant of ursus. Interestingly, Stallings and Turner (1956: p.8) speculated
on the possibility of Y. thornberi as an ursus larval foodplant.
Two of the five ursus larvae were reared through to adults with the following
dates of emergence: 1 male, 11 April 1973 and 1 male, 28 May 1973. The other three
larvae died in April 1973, one of unknown causes and the remainder from parasitism
by a Braconid, Apanteles megathymi Riley (our determination). The two reared
adult ursus males did not appear to differ from those of typical ursus in the senior
author's collection, and one each will be deposited in the collections of the American
Museum of Natural History, and the Allyn Museum of Entomology.
During the winter of 1971, the senior author had the good fortune to read
a book written by Carl Kauffeld (1969) in which mention is made of seeing a
Megathymus ursus while on a snake collecting trip to the Animas Mountains of
New Mexico (loc. cit.: p. 188). A letter was immediately sent to Mr. Kauffeld inquiring
as to the details surrounding this sight record. The following is a direct quotation
extracted from a letter of reply from Mr. Kauffeld dated December 13, 1971: "I
'Museum Associate in Entomology, Natural History Museum of Los Angeles County
24315 West Las Palmaritas Drive, Glendale, Arizona, 85021
saw the Megathymus quite soon after leaving the camp site at the creek, just off the
trail, in a rather shaded area. There are yuccas and agaves in abundance throughout
the region so if this is a factor "you have it made"! I saw the skipper I mention on
the morning of the 24th of July, 1960. I've never seen another." The only thing that
remained was the confirmation of this sight record by the actual collection of ursus.
Early 1972 was marked by additional correspondence with Mr. Kauffeld
and also with Mr. Chuck Hanson, Curator of Mammals at the Arizona-Sonora
Desert Museum, Tucson, Arizona, in order to secure more details surrounding the
sight record, and to obtain a hand-drawn map and directions to the area from the
On 8 April 1972, the senior author, in company with Dr. Frank F. Hasbrouck
of Arizona State University, collected two larvae of ursus feeding in Yucca schottii
Engelmann (a known foodplant of typical ursus) which were growing on very steep
slopes in upper Indian Creek Canyon, Animas Mountains, Hidalgo County, New
Mexico. The larvae were reared to adults and two males were produced in June 1972.
These differed slightly from those of typical ursus. A subsequent collecting trip
to the same locality, in the company of Joseph R. Wielgus, on 27 April 1973, result-
ed in the collecting of another two ursus larvae, and a pupa of an un-named
Megathymus, all in schottii plants! A diligent search of the yuccas that day also re-
vealed that several Megathymid larvae had died in early instars, another pupa of
the un-named Megathymus was found to be parasitized by a Tachinid, and two old
tents were discovered which indicated earlier emergences. The one viable un-named
Megathymus pupa closed a female of the coloradensis complex on 1 May 1973
which differed radically from those of arizonae in the senior author's collection.
The Y. schottii in the Indian Creek locality grows in sparse colonies on open,
steep, rocky slopes and also in the mixed oak and pine woodland farther upcanyon.
The ursus and the un-named Megathymus, both utilizing the same foodplant, are
nowhere common in this locality, but are probably more widespread in the range
than our collecting indicates. It is too soon to tell if the ursus occurring in this isolated
range is subspecifically distinct from typical ursus. At the present time, we are
tentatively assigning the Animas Mountains ursus population to ursus ursus.
We could find no previous records in the literature of the occurrence of
typical ursus in New Mexico. Correspondence with Dr. Frederick H. Rindge,
American Museum of Natural History; Dr. J. F. Gates Clarke, United States
National Museum; and Mr. Julian P. Donahue, Los Angeles County Museum of
Natural History, revealed (in litt.) no typical ursus from New Mexico in the col-
lections under their care. Thus, we believe that the ursus sighting in 1960 by Kauffeld
and our reared male specimens represent the first state records of the occurrence
of typical ursus in New Mexico, and the easternmost extension of the subspecies.
It is unfortunate that both of the ursus larvae collected in the Animas
Mountains in April 1973 died of parasitism by a Braconid (determination pending)
on 13 June 1973, for we have yet to obtain a female. However, the two specimens
obtained in 1972 will be deposited in the following institutions: 1 male, 12 June 1972,
Insect Collection of Arizona State University, and 1 male, 15 June 1972, Allyn
Museum of Entomology. The un-named Megathymus will remain in the collection
of the senior author pending further study.
In our paper describing a new subspecies of ursus (Wielgus, et al, 1972),
mention is made of the collection of four larvae of Megathymus ursus desert
Wielgus, Wielgus and Wielgus from Thirteen Mile Rock, 13 miles southeast of
Camp Verde, Yavapai County, Arizona, on 21 November 1972. These were suc-
cessfully reared to adults and produced the following: 1 female, 20 May 1973;
1 male, 24 May 1973; 1 male, 27 May 1973 and 1 male, 1 June 1973. One specimen of
each, respectively, will be deposited in the collections of the American Museum of
Natural History, Los Angeles County Museum of Natural History, United States
National Museum and the Allyn Museum of Entomology.
The authors are deeply indebted to Mr. Carl Kauffeld for his valuable
comments and suggestions which led to the verification of the Animas Mountains
ursus population, and to Mr. Chuck Hanson for the map and directions to that
unique area of New Mexico. Thanks are sincerely due Mssrs. Don B. Stallings and
Lloyd M. Martin for their unselfish responses to our many inquiries. Without the
help of the following individuals, our task would have been far more difficult
and we are, therefore, most thankful to Dr. Frederick H. Rindge, Dr. J. F. Gates
Clarke and Mr. Julian P. Donahue, for researching the ursus collections under their
We are again grateful to Mr. A. C. Allyn and Dr. Lee D. Miller of the Allyn
Museum of Entomology for making the publication of this paper possible.
In the description of a new subspecies of ursus (Wielgus, et al, 1972) a
typesetter's error resulted in the addition of one extra female paratype to the
American Museum of Natural History. The correct number of paratypes dis-
tributed to this institution should be 2 males and 1 female.
DOS PASSOS, C. F., 1964. A synonymic list of the Nearctic Rhopalocera. Lepid.
Soc. Mem., No. 1, New Haven, Conn. v + 145 pp.
FREEMAN, H. A., 1969. Systematic review of the Megathymidae. J. Lep. Soc., 23,
Supplement 1, 58 pp., 1 pl.
KAUFFELD, Carl, 1969. Snakes: The keeper and the kept. Doubleday and Co., Inc.,
Garden City, N. Y. 248 pp.
STALLINGS, DON B. and J. R. TURNER, 1956. Notes on Megathymus ursus,
with description of a related new species. Lepid. News, 10: 1-8.
TINKHAM, E. R., 1954. The biology and description of a new giant skipper from
Arizona. Bull. So. Calif. Acad. Sci., 53: 75-87, 2 pls.
WIELGUS, RONALD S., JOSEPH R. and DALE, 1972. A new subspecies of
Megathymus ursus Poling (Megathymidae) from Arizona with observations
and notes on its distribution and life history. Bull. Allyn Mus. 9: 1-11.