Common Name: Snout butterfly
Scientific Name: Libytheana bachmanii (Kirtland) (Also called Libytheana carinenta (Cramer)
Description: Snout butterflies have a prominent “snout” formed by elongated mouthparts (labial palpi). Wings (7/8 inch long fore wing length) are patterned on black-brown with white and orange markings. The fore wings have a distinctive squared off, hook-like (falcate) tip. Caterpillars appear humpbacked, having a small head, swollen first and second abdominal segments, and a last abdominal segment that is tapered and rounded. They are dark green with yellow stripes along the top and sides of the body, and have two black tubercles on the top of the thorax. There are two subspecies that occur in the state; L. b. bachmanii (Kirtland) and L. b. larvata (Strecker). The later is larger and darker and the tip (apex) of the fore wing and outer edge of the hind wing are straighter.
Libytheana carinenta mexicana Michener, the only other species in this family also occurs in southern Texas. It differs from L. bachmanii in that the orange coloration is paler and the tip (apex) of the fore wing and outer edge of the hind wing are straighter.
Life Cycle: Winter is spent in the adult stage. Adults apparently mate during the night. Females lay eggs on host plants. Caterpillars hatching from eggs develop though several caterpillar stages (instars) and a pupa (chrysalis) to adult in 15 to 17 days. There may be up to four generations per year.
Habitat and Food Source(s): Caterpillars have chewing mouthparts. Adults have siphoning mouths. The primary food plant for caterpillars are hackberry (Celtis) tree species. Caterpillars feed on tender foliage. Adults are frequently attracted to fermenting fruit and visit wildflowers. Males are encountered around host trees. When at rest, wings are held closed, over the body and appear to mimic dead leaves.
Pest Status: Known for its mass (northward) migrations which occur at irregular intervals when populations explode in the south and southwest. They may become so numerous as to darken the sky. One of these migrations was reported south of San Antonio in mid-September, 1996, where countless butterflies were observed flying across highways.
Literature: Howe 1975; Opler & Rizek 1984.