Callirhytis hartmani, new species

Host. — Quercus chrysolepis Liebmann.

Gall. — Large area of greatly thickened bark causing a large swelling at the base of saplings or rough swollen areas at the crown of large trees, especially on callus tissue. This thickened bark contains hundreds of larval cells about 6 mm. long. Such areas also occur where a limb bends over and the elbow touches the ground. The bark becomes over an inch thick and the wood underneath very rough and knotty. On trees in moist gulches.

Type locality. — Los Gatos, California. The type galls containing living adults were collected November 2, 1918, by Mr. R. D. Hartman and sent in under Hopkins No. 15922 a and placed in rearing at the Eastern Station, East Falls Church, Virginia. The flies emerged April 9, 16, 26, 1919. The writer saw old galls in the San Gabriel Mountains on August 8, 1916, near Coldbrook camp, and at Camp Baldy on June 17, 1918. Empty galls were also seen at St. Helena, California, on May 28, 1918. On May 13, 1918, while collecting with Mr. Hartman at Los Gatos, galls were found in which there was a thick layer of translucent nutritive tissue with no larval cell visible. These were perhaps formed by the flies that had emerged earlier in spring.

- LH Weld: (1921) American gallflies of the family Cynipidae producing subterranean galls on oak^©

Reference: https://www.biodiversitylibrary.org/page/7562993#page/268/mode/1up