Compsodryoxenus tenuis, new species

Host. — Quercus fendleri Liebmann.

Gall. — A slight gradual enlargement at crown of small saplings which are 3-15 mm. in diameter. The larval cells are not scattered uniformly but occur in nests of three or four to a dozen cells under the bark in a sort of depression or pocket in the wood. The cells are white, brittle, thin-walled, about 2-3 mm. in diameter.

Type locality. — Trinidad, Colorado. The type galls were collected July 10, 1916. They then contained pupae, and when cut open September 16 living flies were obtained. Natural emergence date unknown. Similar but larger old galls were collected at Las Vegas, New Mexico.

Loxaulus tenuis (Weld)

Compsodryoxenus tenuis Weld
Loxaulus tenuis Weld

Distribution.--CO, NM

Biology.--Only the unisexual generation is known. It induces stem-swelling galls on Quercus undulata with larval cells hidden under the bark. The slight subterranean enlargements of the stem are about 3-15 mm in diameter. Cells are not scattered uniformly under the bark but situated in groups of 3 to 12 cells in depressions of the wood. Galls occur in July. Adult wasps were dissected from galls in September.