Length: 8-11 mm to apex of abdomen
Morrison (1940) gave several key characters of genus Gonia, including: "head very much inflated (except in G. distincta Smith), yellowish except on the occiput and the eyes, ... ocellar bristles strong and curved backward, orbitals present in both sexes, eyes bare."
Gonia frontosa is parasitic on caterpillars in the family Noctuidae. The microtype eggs are laid on foliage, where the caterpillar consumes them and the fly larvae develop internally. There is also at least one record of Gonia frontosa parasitizing a Blister Beetle, Tetraonyx quadrimaculata (the name is also given as Tetraonyx quadrimaculatus).
Gonia frontosa was the first American species described in the genus. Its author was the great naturalist Thomas Say, who penned his description of this interesting group in 1829.
Morrison (1940) mused, "Considering the widespread distribution of this species, it is probably the oldest form, phylogenetically speaking."
Immediately above: One key trait of Gonia is prominent ocellar bristles that are curved toward the rear.
Insects of West Virginia