Andricus costatus

Quercus gambelii, subturbinella [turbinella]
Acorn galls
Fig 19

Andricus costatus, new species

Host. — An undetermined oak.

Gall (pl. 2, fig. 17). — A depressed ribbed sphere produced in July on the side of acorn cup of several species of white oaks in the Southwest. The gall measures 3.0 mm. in diameter, the ribbed structure showing best on underside when detached.

Habitat. — The single adult emerged on April 5, 1942, from a gall collected on an undetermined oak by Mrs. N. W. Capron in July 1940 at Indian Creek, near Prescott, Ariz. Similar galls have been seen by the writer on Q. fendleri at Trinidad, Colo., and Shoemaker, N. . ; on Q. subturbinella at Tijeras, N. Mex., and on Q. gambelii at Flag- staff, Ariz.