Mary's Giant-Skipper (Agathymus mariae [Barnes & Benjamin])
Wing span: 1 5/8 - 1 7/8 inches (4.2 - 4.8 cm).
Identification: Upperside is black-brown with olive scales at the wing bases. Both wings have bands of yellow spots separated by black veins; spot bands of the female are wider. Underside of hindwing is gray with faint dark markings and a sometimes vague light-colored band.
Life history: From early morning to noon males perch near host plants to wait for receptive females. Eggs are laid singly on the host and fall to the base of the plant. A young caterpillar crawls to a leaf tip and burrows inside where it eats pulp and then hibernates. In the spring the caterpillar makes a new burrow in a leaf base where it feeds on sap until becoming inactive in the summer. Before pupating, the caterpillar enlarges the opening of its burrow and makes a silk trap door from which the adult can emerge.
Flight: One brood from September-November.
Caterpillar hosts: Lechuguilla (Agave lechuguilla).
Adult food: Females do not feed; males sip moisture from mud.
Habitat: Thorn forest and desert hills.
Range: Southern New Mexico, west 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.
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.