Species Furcula occidentalis - Western Furcula - Hodges#7939

7939

Double-lined Furcula

Willow Kitten

OCCIDENTALIS: occidental means western (as opposed to oriental - eastern); generally refers to the western hemisphere

Three other Furcula species in North America are distributed, like occidentalis, from the east coast to the west coast, so there is nothing uniquely western about this species.

wingspan 32-45 mm

Adult:

forewing pale grayish with dark gray to charcoal median band and dark gray to charcoal patch along costa near apex; PM line triple, fine, continuous across wing presenting 3 distinct 'teeth' in the two most distal PM lines; AM and terminal lines composed of several large black dots; some yellow or orange coloration often present next to AM and PM lines, and sometimes in a band of color across top of thorax

hindwing pale grayish-white with black-dotted terminal line and dark discal spot

Larva: body lime green with continuous dorsal blue-green and brown saddle extending down toward second abdominal proleg; saddle outlined in yellow; rear of second thoracic segment with raised transverse ridge; tails (anal prolegs) have extrusible portion brown with pale subapical band

[adapted from description by David Wagner and Valerie Giles)

Alberta to Newfoundland south to Iowa, Ohio and New Jersey with populations in Colorado and New Mexico. (1)

adults fly from April to August

larvae from June to September

larvae feed mostly on willow, and sometimes poplar

overwinters as a pupa; one or two generations per year

Larva; larva; adult

Furcula furcula (Clerk, 1759) is found in BC, AB, MT, UT, CO, NM (1)

Light areas of forewing are white in F. borealis and scolopendrina, and pale tan or yellowish in modesta; dark gray areas are lacking in forewing of cinerea; PM line is either not triple or not continuous in other species (compare images of all 5 species)

The southwestern species F. nivea has a mostly white forewing.

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Butterflies and Moths of North America

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