No. 2368. AMERICAN SUBTERRANEAN GALLS ON OAK— WELD. 237 



gin ciliate. Abdomen broader than long, smooth and polished, second 

 segment occupying about half the length. Hypopygium prominent, 

 ventral spine twice as long as broad, ventral valves protruding at an 

 oblique angle, ovipositor when dissected out longer than antenna. 

 Using width of head as a base, the length of mesonotum ratio is 1.2- 

 1.3; antenna, 2.4; ovipositor, 3.1-3.3; wing, 3.2. 



Range in length of 15 pinned specimens 1.9-2.2 mm. Average, 

 2.0 mm. 



Type.— -Cat. No. 22831, U. S. N. M. Type and 8 paratypes. 



Host. — Quercus chapmani Sargent and Quercus stellata Wangen- 



heim. 



Gall. — A slight spindle-shaped enlargement at base of one-year- 

 old sprouts in patches of runner oak. In autumn they are on current 

 year's growth. Maximum diameter of gall is about twice that of 

 normal shoot. Cells are scattered, not nested, just under the bark, 

 about 1.5 by 2.0 mm. and extending about 1.25 mm. into the wood, 

 the deeper part narrower. 



Habitat. — Type locality, Ocala, Florida. The galls were collected 

 October 30, 1919, in a patch of Quercus chapmani, Hopkins U. S. No. 

 15634c. These galls then contained larvae and pupae. The type 

 fly was cut out January 12, 1920. Other galls were collected on same 

 oak at Green Cove Springs, November 23, 1919, containing adults 

 which were cut out on December 1. One gall was taken on Quercus 

 stellata October 11 at Marianna, and lighter colored flies similar in 

 structure were cut out December 6. 



Genus BELONOCNEMA Mayr. 



This genus is based on a species producing a fleshy root gall on 

 live oak in Florida. Ashmead described it as Dryorhizoxenus fiori- 

 danus and sent material to Europe where Mayr described it also. 

 In Transactions American Entomological Society (vol. 13, p. 63), 

 Ashmead acknowledges that Mayr's name of Belonocnema treatae has 

 precedence. In Verhandlungen der kaiserlich-koniglichen zoologisch- 

 botanischen Gesellschaft in Wien (vol. 52, p. 287), Mayr states that 

 the correct spelling of his genus is Belonocnema. 



In Psyche (vol. 10, p. 150) Ashmead has erroneously placed the 

 genus in that section of the key with undeveloped wings, whereas flies 

 of both sexes have normal wings. He also erred in considering the 

 palpi as 6- and 4-segmented. Balsam mounts of type material show 

 that the maxillary palpi are 5- and the labial 3-segmented. If the 

 scutellum is considered to have an arcuate furrow at the base without 

 pits, the genus would run in the Ashmead key to Dryocosmus, and if 

 bifoveolate as Ashmead stated to Biorhiza. From either it is easily 

 separated by the characteristic spur at the apex of the front tibiae 

 and by the clouded veins about the short marginal cell. 



