Trigonaspis radicola (Ashmead)

Dryophanta radicola
Diplolepis radicola

The galls of this species occur in clusters of a dozen or less, bursting out through the bark just below the surface of the ground in places where there is an abundance of humus at the base of tree or stump of Quercus alba Linnaeus. They are of white, soft, succulent tissue, rounded at end, but compressed into wedge shapes on sides, sometimes rosy if exposed. They develop rapidly in spring, becoming full grown and maturing the flies in about a month and then decaying. The writer has collected the galls at Miller, Indiana; Winnetka and Fort Sheridan, Illinois. Growing galls can be found in late May and the flies issue June 12-26, although in the late season of 1912 the first to issue came out on June 22, and they continued to come out until July 1. Males issue first. The fact that in 36 cases these galls were found at the base of stumps whose sprouts carried last year's oak- fig galls leads to the suspicion that this may be the alternating sexual generation of the wingless Biorhiza forticornis (Walsh). In one case there was failure to find them, and in one they were found where there were no fig galls. The radicola adults issuing in June are good fliers and are thought to fly to developing sprouts where they lay eggs and produce the fig galls in the fall. From these wingless adults (all females) issue in winter (in late December or in February and March in breeding cage) to crawl down to base of same sprouts and lay eggs to produce this radicola gall in the spring. This cycle is not proven, and it remains for others to work out the details of the life history. Brodie was the first to suggest a connection between the fig gall and a root gall when in Annals of Report of Clerk Board Forestry, Ontario, 1896 (pp. 114-116), he says forticornis burrows into ground finding rootlets a few inches down in which they oviposit and in which are formed subterranean galls, but he does not describe them further. Radicola is not on "rootlets," but at base of tree. In the forest insect collection at the United States National Museum are three males and three females of what seem to be this species reared in March, 1897, at Shovel Mount, Texas, by F. G. Schaupp "on roots of post oak."

Xanthoteras radicola sex. gen.

Quercus alba, chapmani, stellata
"Root" galls
Cluster of fleshy white galls at base of sprouts which bear old oak fig galls. In early spring.

[Photo caption]
On Q alba. Also on Q chapmani. Galls are found in late May. Adults emerged June 12-26 (IL). In 36 cases these galls were found at the base of stumps whose sprouts carried last years Oak Fig Galls (Xanthoteras forticorne).

Dryophanta radicola, new species

Gall.--This gall also could not be found in the collection. The Note Book says: Received from JG Barlow, Cadet, Missouri, one much shriveled gall, found on the roots of scrub oak.

Reared May 21, 1886.

Trigonaspis radicola (Ashmead) comb. nov.

Seven Xanthoteras species here are transferred to Trigonaspis. . . Trigonaspis radicola (Ashmead) comb. nov.

Xanthoteras radicola (Ashmead 1896)

Hosts: Quercus chapmanii

[Sexual generation root gall found in Florida in the spring.]