Callirhytis petrosa, new species
Host. — Quercus brevifolia Sargent. [Quercus incana]
Gall. — A mass of confluent woody cells inside the acorn in place of the normal cotyledons. Found in fall affecting acorns of current season's crop and causing them to be more or less stunted in size.
Habitat. — The type locality is Palestine, Texas, where affected acorns were collected October 16, 1917. Five living flies were cut out of galls on December 1, 1919, and as full-grown larvae were also found the emergence is distributed over at least two seasons. The normal emergence is probably in the spring. Similar galls were seen at Ocala and at St. Petersburg, Florida, in autumn of 1919.
Callirhytis corrugis (Bassett)
This species was described from one specimen taken on May 11 at Waterbury, Connecticut, from the claws of a spider on flowers of Q. prinoides. It is preserved in the Academy of Natural Sciences, Philadelphia, where the writer has examined it. It is a Callirhytis with nonciliate fore wings, pale venation, simple claws, and is clearly related to those species known to have been reared from stone galls in acorns. The mesoscutum is rugose all over, not tranversely so, coarser behind, the transverse groove at base of scutellum is rugose and of uniform width so that disk is rounded in front, the carinae of propodeum converge slightly above and the first and second cross-veins are not clouded. Determined as this species without direct comparison with the type, the writer has specimens taken at Great Falls, Virginia, and others taken ovipositing in buds of Q. coccinea at Washington on March 27, 1921. Some of these specimens have 13 and others 14 segments in antenna, while corrugis was described as 14-segmented, but the number may vary. If these are correctly determined the only character so far found to separate them from petrosa Weld is the length of the ovipositor, ratio 3.26 in petrosa and 4.8 in those determined as corrugis. The gall of corrugis is still unknown. The sculpture of the fly suggests that it came from a stone gall in an acorn, probably on coccinea or ilicifolia. The alternating generation is also unknown.