No. 2368. AMERICAN SUBTERRANEAN GALLS ON OAK— WELD. 203 



Host. — Quercus douglasii Hooker and Arnott. 



Gall. — An underground cluster of fleshy white galls at base of 

 stumps similar to galls of T. radicola (Ashmead), but with longer and 

 more slender pedicels. After flies emerge the galls decay. In May. 



Type locality. — Los Gatos, California. Paratypes from Paso 

 Robles also. 



Biology. — Collected at Los Gatos May 14, 1918, when galls contained 

 pupae and exit holes showed where some adults had already emerged. 

 In breeding cages three males issued May 16 and three more on May 

 17. At Paso Robles on May 6 galls contained larvae and pupae. In 

 cage four adults issued by May 13, six by May 25, and one June 2. 



8. TRIGONASPIS RADICOLA (Ashmead). 



Plate 30, fig. 8. 



Dryophanta radicola Ashmead, Proc. U. S. Nat. Mus., vol. 19, 1896, p. 116, No. 5. — 



Bridwell, Trans. Kan. Acad. Sci., vol. 16, 1899, p. 204.— Cook, 29th Rept. 



Dept. Geol. & Nat. Res. Indiana (1904), 1905, p. 836, fig. 29; Proc. Ind. Acad. 



Sci., (1904), 1905, p. 225. — Beutenmueller, Bull. Amer. Mus. Nat. Hist., vol. 



30, 1911, p. 354, pi. 15, figs. 9-10.— Thompson, Cat. Amer. Ins. Galls, 1915, p. 5 



and p. 38.— Felt, Key to Amer. Ins. Galls N. Y. St. Mus., Bull. 200, 1918, p. 



54, fig. 87, 9-10. 

 Dryophanta radicicola Dalla Torre and Kieffer, in Wytsman Gen. Ins. Cyni- 



pidae, 1902, p. 53, No. 36. 

 Amphibolips radicola Ashmead, Cook, Ohio Nat., vol. 4, 1904, p. 117, figs. 76 a 



and b. 

 Diplolepis radicola Ashmead, Dalla Torre and Kieffer, Das Tierreich, Lief. 



24, 1910, p. 360. 



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, some- 

 times 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 Biorliiza foriicornis (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 



