Attributes of Agathymus stephensi

California Giant-Skipper
Agathymus stephensi (Skinner, 1912)

Family: Hesperiidae
Subfamily: Megathyminae
Identification: Fringes are distinctly checkered. Upperside is brown-black with yellowish scales at the wing bases and cream-colored spots. Hindwing spot band is curved and there is usually a spot in the cell. Underside of hindwing is mottled gray with irregular bands of cream-colored spots.
Wing Span: 2 - 2 1/4 inches (5.1 - 5.7 cm).
Life History: The adults roost on bushes, the males usually in canyon bottoms. 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 make 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.
Flight: One brood from September-October.
Caterpillar Hosts: Desert agave (Agave deserti).
Adult Food: Females do not feed; males sip moisture from mud.
Habitat: Sonoran desert.
Range: The Colorado Desert in Riverside and San Diego counties, California; Baja California Norte.
Conservation: Populations and their habitats should be conserved wherever found.
NCGR: G2 - Imperiled globally because of rarity (6 to 20 occurrences), or because of other factors demonstrably making it very vulnerable to extinction throughout its range. (Endangered throughout its range).
Management Needs: Conserve habitat and discourage overgrazing.
Taxonomy Notes:

Images of Agathymus stephensi

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Agathymus stephensi - stephe~1.jpg

Agathymus stephensi - stephe~1.jpg

The map below displays all BAMONA data for this species and has three different data layers:
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Observation Date Submitter Region Verified Datesort icon
January 01, 1950 legacy.reporter Riverside County, California, United States December 31, 2004 Details
January 01, 1950 legacy.reporter San Diego County, California, United States December 31, 2004 Details
January 01, 1950 legacy.reporter Imperial County, California, United States December 31, 2004 Details
January 01, 1950 legacy.reporter Baja California Norte, Mexico December 31, 2004 Details
October 04, 1986 Ken Davenport (Ken Davenport) San Diego County, California, United States August 07, 2009 Details
October 04, 1986 Ken Davenport (Ken Davenport) San Diego County, California, United States August 07, 2009 Details
October 16, 1936 legacy.reporter (John A. Comstock) San Diego County, California, United States August 07, 2009 Details
September 30, 1934 legacy.reporter (Not given) Riverside County, California, United States August 07, 2009 Details
October 18, 1965 legacy.reporter (J. W. Tilden) San Diego County, California, United States October 16, 2009 Details
October 20, 1956 legacy.reporter (H. Avery Freeman) San Diego County, California, United States December 17, 2009 Details
October 10, 1922 legacy.reporter (George Field) San Diego County, California, United States January 05, 2010 Details
September 19, 1993 legacy.reporter (Jeffrey Glassberg) San Diego County, California, United States January 05, 2010 Details
September 23, 1973 legacy.reporter (J. Emmel, R. Highton) Riverside County, California, United States January 06, 2010 Details
October 17, 1976 legacy.reporter (Oakley Shields) Imperial County, California, United States January 07, 2010 Details
October 08, 2007 legacy.reporter (Kojiro Shiraiwa) San Diego County, California, United States December 31, 2010 Details
October 11, 2007 legacy.reporter (Kim Davis & Mike Stangeland) San Diego County, California, United States December 31, 2010 Details
October 01, 2005 legacy.reporter (unknown) San Diego County, California, United States December 31, 2010 Details
October 04, 2004 legacy.reporter (William Bouton) San Diego County, California, United States December 31, 2010 Details
September 28, 2013 Robert Gorman San Diego County, California, United States October 06, 2013 Details
September 29, 2013 Robert Gorman San Diego County, California, United States October 06, 2013 Details
September 29, 2013 Robert Gorman San Diego County, California, United States October 30, 2013 Details
September 28, 2013 Robert Gorman San Diego County, California, United States March 29, 2014 Details