Skippers: Mary’s giant-skipper (Agathymus mariae)

(Lepidoptera: Hesperiidae: Megathyminae: Aegialini)

Profile prepared by Mace Vaughan and Matthew Shepherd, The Xerces Society for Invertebrate Conservation

Mary’s giant-skipper is found in desert scrub in Chihuahua and Coachila and just north of the border in southern Texas and New Mexico. Its larval hostplant is lechuguilla agave, a plant that is threatened by grazing, fire, and plant collectors. The lack of information on this species, particularly on its populations in Mexico, means that it cannot be shown to be secure. More research is required to establish its status.

red list profile

conservation status

Xerces Red List Status: Data Deficient
Other Rankings:

Canada – Species at Risk Act: N/A
Canada – provincial status: N/A
Mexico: None
USA – Endangered Species Act: None
USA – state status: None
NatureServe: G3G4
IUCN Red List: N/A

This species is designated Data Deficient because of the lack of information about its abundance and distribution in the Mexican part of its range. There are a number of threats to its habitat and it has a restricted distribution.

description and taxonomic status

Mary’s giant-skipper is a medium sized butterfly in the family Hesperiidae. Its wingspan is 42 to 48 mm.

The upperside is black-brown with olive scales at the wing bases and a pale border. Both wings have postmarginal bands of yellow spots. These bands are wider on females. Underside of the wings are gray with faint dark markings. The forewings have a darker brown patch and the hindwings sometimes have a vague, light-colored, postmedian band.

Agathymus mariae (complex including gilberti) (Barnes & Benjamin), 1924.

life history

Habitat is desert hills and thorn scrub. The larval hostplant is lechuguilla agave (Agave lechuguilla).

There is one flight from September to November. During this time adults do not feed, although males sip moisture from mud. Males perch near the hostplant during the morning. Females will lay eggs singly on the host. These fall to the base of the plant from where the young caterpillar hatches and crawls to a leaf tip where it burrows inside to eat the pulp and then hibernate. In the spring the caterpillar makes a new burrow in a leaf base where it feeds on sap until ceasing activity for the summer. Before pupating, the caterpillar enlarges the opening of its burrow and makes a silk trap door from which the adult can emerge.


Southern New Mexico, southwestern Texas, and northern Mexico (Chihuahua and Coachila).

Courtesy of Butterflies and Moths of North America, Big Sky Institute.

threats and conservation needs

The principal threats are from grazing, wildfire, and plant collectors. All of these reduce the availability of the agave larval hostplant.

Protection of its habitat and ensuring adequate abundance of larval hostplants.

Additional research into appropriate habitat management and surveys to establish current population sizes and locations, especially in Mexico.


Bailowitz, R. A., and J. P. Brock. 1991. Butterflies of Southeastern Arizona. Sonoran Arthropod Studies, Inc., Tucson, AZ.

Boniwell, J. C. 1931. Notes on AGATHYMUS MARIAE Barnes and Benjamin. Annals of the Carnegie Museum 20:264-265.

Freeman, H. A. 1964. Larval habits of AGATHYMUS MARIAE. Journal of the Research on the Lepidoptera 3:145-147.

MacNeill, C. D. 1975. Superfamily Hesperioidea. Pages 411-578 in: W.H. Howe, editor. The Butterflies of North America. Doubleday and Co., Garden City, NY.

Opler, P. A., and A. B. Wright. 1999. A Field Guide to Western Butterflies. Second edition. Peterson Field Guides. Houghton Mifflin Company, Boston, MA.

Opler, P. A. (chair), J. M. Burns, J. D. LaFontaine, R. K. Robbins, and F. Sperling. 1998. Scientific Names of North American Butterflies. Fort Collins, CO.

Scott, J. A. 1986. The Butterflies of North America. Stanford University Press, Stanford CA.

Stallings, D. B., V. N. T. Stallings, J. R. Turner, and B. R. Turner. 1985. Courtship and oviposition patterns of tow AGATHYMUS (Megathymidae). Journal of the Lepidopterists’ Society 39:171-176

Stallings, D. B., J. R. Turner, and V. N. Stallings. 1961. A new subspecies of AGATHYMUS MARIAE from Mexico. Journal of the Lepidopterists’ Society 15:19-22.

Stanford, R. E. and P. A. Opler. 1993. Atlas of Western USA Butterflies. Denver and Fort Collins, CO.

additional resources

Big Sky Institute, Butterflies and Moths of North America: Mary’s giant-skipper (Accessed 1/21/09)

Nearctica; The Butterflies and Skippers of North America: Mary’s giant-skipper (Accessed 5/4/05)

NatureServe Explorer (Accessed 9/23/08)


Vaughan, D. M., and M. D. Shepherd. 2005. Species Profile: Agathymus mariae. In Shepherd, M. D., D. M. Vaughan, and S. H. Black (Eds). Red List of Pollinator Insects of North America. CD-ROM Version 1 (May 2005). Portland, OR: The Xerces Society for Invertebrate Conservation.


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