No.236S. AMERICAN SUBTERRANEAN GALLS ON OAK— WELD. 231 



teenth without evidence of fusion. Mesoscutum coriaceous with 

 scattered setigerous punctures, parapsides percurrent, lateral and 

 parallel lines present and a broken row of large punctures forming an 

 incomplete median. Scutcllum coarsely pitted and rugose behind 

 with smoothish spot on disk just behind the two distinctly separated 

 pits, impressed areas on sides. Propodeum with two slightly curved 

 ridges inclosing a smooth area broader than high. Legs with hind 

 tarsus shorter than tibia, second and fifth subcqual, claws simple. 

 Wings with brownish veins, those beyond second cross-vein faint, 

 first abscissa of radius arcuate, second not reaching margin, areolet 

 small and indistinct, margin not ciliate. Abdomen compressed, 

 longer than high, second segment occupying over four-fifths with 

 ring of hairs at base, ventral valve in balsam twice as long as broad, 

 ovipositor when dissected out a little longer than antenna. Using 

 width of head as a base, the length of mesonotum ratio is 1.1; an- 

 tenna, 2.2; ovipositor, 2.3-2.5; wing, 3.0. 



Male. — Body darker but not black, antennae 2.8 times width of 

 head. 



Length of 38 pinned females, 2.2-2.7 mm. Average, 2.4 mm. 

 Length of each of the three Jacksonville males, 2.2 mm. 



Gall. — Photographed from galls on Quercus catesbaei Michaux col- 

 lected at Jacksonville, Florida. In the late fall the galls contain a 

 thick translucent nutritive layer in each cell. They should be col- 

 lected in the spring for rearing. 



Host. — It was described from Quercus laurifolia Michaux. The 

 writer has collected galls on nine other species of oak, as shown 

 below. 



Habitat. — From Quercus catesbaei at Ocala and Jacksonville, 

 Florida, galls were taken and adults of both sexes reared that agree 

 with the types in the United States National Museum. They were 

 collected April 21 and April 25, 1914, and the flies emerged and died 

 in the box before August 10. Galls of this species and on this host 

 were seen at Green Cove Springs, Ocala, Madison, and Gainesville, 

 Florida. Galls have been taken, but no flies reared from the fol- 

 lowing oaks: 



Q. rubra Linnaeus at Ravinia, Fort Sheridan, Highland Park, and 

 Evanston, Illinois. 



Q. coccinea Wangenheim at Millers, Indiana, and Evanston, Illi- 

 nois. 



Q. velutina Lamarck at Hot Springs, Arkansas. 



Q.falcata Michaux at Gainesville, Florida. 



Q. texana Buckley at Boerne and Kerrville, Texas. 



Q. marilandica Muenchhausen at Mineola, Texas, and Hot Springs, 

 Arkansas. 



Q. brevifolia Sargent at Marianna and Ocala, Florida. 



Q. myrtifolia Willdenow at Carrabelle and Daytona, Florida. 



