210 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.59. 



Genus ODONTOCYNPS Kieffer. 



14. ODONTOCYNIPS NEBULOSA Kieffer. 



Plate 31, fig. 12. 



Odontocynips nebulosa Kieffer, Bull. Laboro. Zool. Portici, vol. 4, 1910, p. 112, 

 Female. — Dalla Torre, in Krancher Ento. Jahrb., 20 Jahrg., 1910, p. 176.— 

 Felt, Key to Amer. Ins. Galls, N. Y. St. Mus., Bull. 200, 1918, p. 54— Beuten- 

 mueller, Ent. News, vol. 29, 1918, p. 329. 



This new genus and species was described in 1910 from flies only, 

 captured in Georgia by King and in Texas by Boll. The types are in 

 the Museum of Zoology, Berlin. 



The writer recognized the genus in March, 1917, in specimens from 

 Woodstock, Georgia, bred from a root gall on oak received by Doctor 

 Felt and submitted to William Beutenmueller for examination. The 

 flies agree fairly well with the published description of nebulosa 

 Kieffer. As the only description of the gall is the brief characteriza- 

 tion by Doctor Felt in 1918 in his Key to American Insect Galls 

 (p. 54) as "Irregular, polythalamous root gall, diameter 3.5 cm. on 

 Q. minor," a more extended description may be given here. 



Host. — Quercus stellata Wangenheim. 



Gall. — On the roots of young shoots that come up under larger 

 trees. These shoots are only 30-90 cm. high and often occur in 

 large numbers so that their tangled roots form a mat, and it is on 

 these horizontal roots where the thicket is dense enough to accumu- 

 late humus that the galls are found. They occur on roots 5-15 mm. 

 in diameter and are sometimes 5-10 cm. underground. Single galls 

 are globular, 10-13 mm. in diameter, but they are usually aggregated 

 into irregular lobed polythalamous masses as large as a man's fist 

 or 8 cm. in diameter. They are covered with smooth bark, light 

 colored like the normal bark of roots, but brown when dry. They 

 are easily cut when fresh, but very hard and woody when dry. The 

 larval cavities are about 6-8 mm. in diameter and the walls about 

 2 mm. thick. Exit holes 3 mm. in diameter. They are often attacked 

 by whitish wingless plant lice attended by a pale yellowish ant. 



Habitat. — The writer first collected the galls on September 9, 1915, 

 at Webster Groves, Missouri, on Quercus stellata. They contained 

 pupae on October 3, and adults October 26, but a few had a thick 

 nutritive layer instead. The galls were buried in soil in greenhouse 

 to determine date of emergence and still contained living flies January 

 17, 1916, but by March 20 all were gone. On October 4, 1917, the 

 same locality was again visited and only one gall found where they 

 had been very abundant two years before. Collected galls at Hoxie, 

 Arkansas, October 10, 1917, and cut out living flies November 16. 

 At Hot Springs, Arkansas, galls contained pupae on October 12. 

 From others collected at Palestine, Texas, October 16, flies emerged 



