About Hypaurotis crysalus (Edwards, 1873)
The Colorado hairstreak (Hypaurotis crysalus) is a montane butterfly native to oak scrubland in the southwestern United States and northern Mexico. In 1996, it was designated the state insect of Colorado, and it is the only species classified in the genus Hypaurotis. The upperside of the Colorado hairstreak’s wings is dark purple, with a broad black or dark border. Each wing has orange spots along its lower outer edge, and each hindwing bears a thin, hairlike tail. The underside of the wings ranges from pale to dark gray, with white and dark markings, an orange patch on the margin of each forewing, and an orange spot with a black center on the hindwing near the tail. This butterfly has a wingspan of 3.1–3.8 cm (1.2–1.5 in). The thin hair-like tails extending from its rear wings are likely the source of the "hairstreak" part of its common name. This species depends on Gambel oak (Quercus gambelii), which is both the preferred roost for adult butterflies and the usual food source for caterpillars. Females lay eggs singly in late summer on twigs of Gambel oaks or other oak species. Caterpillars emerge in the spring and feed on young oak leaves. Adult butterflies feed on tree sap and likely honeydew secreted by other insects, rather than feeding on flowers. This species has one flight period per year, which typically runs from mid-June to August. It is found primarily in the Colorado Plateau states of Utah, Colorado, Arizona, and New Mexico, though small populations also occur in parts of Nevada, Wyoming, and Durango, Mexico.
