Drepana arcuata, the arched hooktip or masked birch caterpillar, is a moth of the family Drepanidae. The species was first described by Francis Walker in 1855.[1] It is found from Newfoundland to Vancouver Island, south to at least North Carolina, South Carolina and California.
The wingspan is 24–. Adults are on wing from mid-May through late-July. There is one generation per year in the north.
The larvae feed on Betula papyrifera and Alnus species, which they may use as a medium to communicate. Sound is produced by shaking their bodies, drumming and scraping their mouthparts, or dragging specialised anal "oars" against the surface of a leaf. Larvae build communal silk shelters and the sounds may attract other larva to the shelter.[2]