Andricus foliosus, new species

Host. — Quercus bicolor and macrocarpa.

Gall (fig. 17). — A fleshy green enlargement of the midrib or one of lateral veins usually on basal third of leaf blade, usually only one on a leaf. "When seen from below there is a bend in midrib at this point and a small depressed spot. On upper side of leaf it shows a rosette of leaf-like rudiments hiding the gall; on the lower a smaller rosette on the concave side of the bond. The gall contains 1-6 larval cavities and the larva is much elongated like those in rose galls. The young galls begin to show about the middle of May when the young leaves are not one-third grown.

Habitat. — The type locality is a tree of Q. bicolor four miles west of Evanston, IL., out Emerson Street. Here the galls were observed year after year for several years. Galls collected June G, 1909, gave flies in numbers June 29 and in early July. In 1912 adults emerged June 20-28. In 1913 they emerged on June 26. In 1916 the flies were mostly out by June 28 and galls beginning to dry up. In 1917 they contained pupae on June 2-1. The paratype locality is a tree of Q. macrocarpa in Winnetka. IL. Miss Howe found galls at Ithaca and Geneva (see thesis) and the writer has seen them at Medina, N. Y.. as well as at Evanston and Moline, IL., on Q. macrocarpa.

Andricus foliaformis, n. sp.

Gall. Small wart-like projections thrown out from the mid-rib on the under side of the leaves from which there grows a leafy expanse that extends on all sides like the corolla of a rotate flower. (Fig. 1.)

Andricus foliosus

Slight local thickening of midrib on leaf of Q. bicolor with a rosette of leafy bracts both above and below. Green, fleshy, containing 1-6 cells, only one on a leaf, usually on the basal third, first appearing in May when the leaves are about one-third grown. Adults emerge in late June.

Andricus foliaformis

Quercus alba
Leaf galls, integral
Known only from original descripton of a single specimen from MI reared July 20. Type fly and gall lost. Andricus foliosus on Q bicolor is a synonym of it.

Quercus bicolor
Leaf galls, integral
A thickening of the midrib bearing a rosette of green filaments which hide the swelling, containing 1-6 cells, in June.

Quercus macrocarpa
Leaf galls, integral
Midrib swelling bearing bracts above and below, containing 1-6 cells. June.

[Photo caption]
Described from Q alba in MI, the holotype and gall now lost. Description of adult and gall agree with Andricus foliosus described from Q bicolor from IL, the adults emerging June 20-25, 1912.

Andricus foliaformis

Small, wartlike midrib galls on the under surface of the leaves and with corollalike processes apically, on Q. alba.

This species was described in 1888 from a single specimen from a gall on a leaf of Q. alba in Michigan. The holotype and gall were not found. No gall like the published figure has since been found on this host. However, Anclricus foliosus Weld was described from a similar gall on Q. hicolor at Evanston, IL. Comparison of these adults with the original description of foliaformis leads to the conclusion that foliosus is a synonym of foliaformis (new synonym).