What is "volucella"

Volucella is a genus of large, broad-bodied, dramatic hover-flies. They have distinctive plumose aristas and the face is extended downward. They are strongly migratory and males are often territorial. Adults feed on nectar of flowers and are often seen sunning on leaves. The larvae of most species live in nests of bumblebees and social wasps, where they are detritivores and larval predators.