Ursine Giant-Skipper (Megathymus ursus Poling)
Wing span: 2 1/2 - 3 inches (6.3 - 7.6 cm).
Identification: Antennal club is white. Upperside is black; forewing has white spots near the apex and a wide band varying from yellow to orange; hindwing has no markings. Underside of hindwing is gray with 2 white spots near the costa.
Life history: Adults have a rapid flight. Females glue eggs singly on leaves of the host. A young caterpillar eats leaf tips and then burrows into the root and makes a tent. Older caterpillars hibernate in their tents and eventually pupate there. Chrysalids can move up and down in their tents.
Flight: One brood from May-August.
Caterpillar hosts: Schott's yucca (Yucca schottii), Arizona yucca (Y. arizonica), banana yucca (Y. baccata), and Torrey's yucca (Y. torreyi).
Adult food: Adults do not feed, but males sip moisture from mud.
Habitat: Grassy shrubland and open yucca-oak woodland.
Range: Rare and local in the mountains of southern Arizona, southern New Mexico, southwest Texas, and northern Mexico.
Conservation: Not usually required.
The Nature Conservancy Global Rank: G3 - Very rare or local throughout its range or found locally in a restricted range (21 to 100 occurrences). (Threatened throughout its range).
Management needs: None reported.
Bailowitz, R. A., and J. P. Brock. 1991. Butterflies of southeastern Arizona. Sonoran Arthropod Studies, Inc., Tucson, Arizona. 342 pages. Scott, J. A. 1986. The butterflies of North America. Stanford University Press, Stanford, Calif. 583 pages, 64 color plates. Stanford, R. E. and P. A. Opler. 1993. Atlas of western USA butterflies including adjacent parts of Canada and Mexico. Denver and Fort Collins, CO. Tilden, J. W. 1986. A field guide to western butterflies. Houghton-Mifflin Co., Boston, Mass. 370 pages, 23 color plates.
Author: Jane M. Struttmann
State and Regional References:
Opler, Paul A. 1999. Peterson Field Guide to Western Butterflies, revised edition. Houghton Mifflin Co., Boston, Mass. Stanford, R.E. and P.A. Opler. 1993. Atlas of Western USA Butterflies. Privately published, Denver, Colo.