Caryomyia biretta Gagne, new species

Hosts: Carya ovata, laciniosa, tomentosa

Gall (Figs. 16, 144): Rare, on Eucarya hickories, but not E of Appalachian Mrs.; on lower leaf surface between veins; 2.5-3.0 mm high, depressed-spheroid, broad apical surface flat to slightly concave with central elongate nipple; hairless, not sticky, green to purple; base with central, shallow, central excavation, the leaf slightly convex and discolored on reverse side; larval chamber basal, depressed-ovoid, lined with yellowish membrane, contrasting with purple, woody tissue surrounding larval chamber, especially laterally. Exteriorly this gall simulates that of C. inflata except that the latter does not have the tassel at the apex. The internal shape of these two galls is very different with the larval chamber of C. biretta being surrounded by thick walls and that of C. inflata being thin walled and surmounted by a false chamber.

Affinities. — See under C. sanguinolenta, from which this species differs in the shape of the gall. [C sanguinolenta: Galls of this species resemble closely enough those of several other species, C. biretta, C. conoidea, C. lunata, C. marginata, and C. stellata, to indicate some relationship among them, given other similarities of adult and larval characters. These species differ only in the shape of their galls, which are conical with their extensive soft, large-celled tissue eventually collapsing. Between that tissue and the larval cell is a pellicle that is at first soft but eventually hardens into a brittle covering. The soft tissue mostly deteriorates during the winter. The base of the galls, through which pupae eventually escape, is shield- like and smooth, even on otherwise hairy galls. The conical galls only superficially resemble those of C. persicoides and C. turbanella. Galls of these last two deteriorate differently and pupae break out of the side of the gall rather than the base. Also, the male antennae and genitalia of these two species place them in another group.]

Range: CT, GA, IL, MA, NH, OH