The antennae, head and thorax are brownish-black and the abdomen yellowish-brown, the underside being paler than the upper side.

[1] The adults emerge in late spring and eggs are laid on the underside of the leaves of goat's beard (Aruncus dioicus) shortly afterwards.

Eggs hatch a week later, releasing gregarious larvae, which consume leaf tissue between the main veins.

Those larvae descend to the ground late in the year, overwinter as pre-pupae, and pupate in the spring.

[2] In heavy infestations, leaves may be skeletonized except for their main veins,[2] and the plants may become completely defoliated.