4g PEOCEEDINGS OF THE NATIONAL, MUSEUM v<.r.. 68 



wider than long, finely and uniformly rugose, parapsidal grooves 

 complete, no median. Disk of scutellum more coarsely rugose, the 

 transverse groove at base rugose, not bounded laterally. Carinae on 

 ])r<)podeum almost straight and parallel with a trace of a median in 

 inclosed area. ]Mesopleura coriaceous, shining. Hind tarsus shorter 

 than tibia, its segments as 37:15:10:7:11 (with claw 14). Claws 

 weak and simple. Wing pubescent, ciliate, with three prominent 

 transverse bands of cloud and three clear areas. The narrowest 

 cloud lies on the basal vein, the next begins at costal hinge and 

 includes the basal half of the radial cell extending back to the anal 

 vein, the largest occupies more than the apical fourth of the wing. 

 The first abscissa of radius is arcuate, the second strongly curved 

 and transparent, no areolet. Abdomen longer than head and thorax, 

 length to height to width as 38 : 27 : 15, inserted obliquely, lengths of 

 tergites along dorsal margin (knife-edged behind second) as 

 54 : 22 : 7 : 10 : 15 : 10, second bare at base, ventral valves slender, 

 prominently protruding obliquely upward, the sheath over the valves 

 of an unusual type, hypopygium long and prominent, the ventral 

 spine slender, in side view two and one-half times as long as broad. 

 Using width of head as a base the length of mesonotum ratio is 1.1, 

 antenna 2.8, ovipositor 5.3, Aving 3,0. Length 1.65-3.45 mm. Average 

 of 102 specimens 2. 06 mm. 



Male. — Differs in having 15-segmented antennae, lengths as 

 15 : 6 : 17 : 19 : 16 : 14.5 : 12 : 12 : 12 : 11 : 11 : 10 : 10 : 9 : 11. Abdomen 

 shorter than thorax, triangular in side view, lengths of tergites as 

 6:42:14:3:0:2:12. Lengths, 1.9-2.6 mm. Average of 36 speci- 

 mens, 2.23 mm. 



Type.— C'At. No. 27197, U.S.N.M. Type, allotype, 12 male and 50 

 female paratypes. Paratypes at American Museum, Field, Stan- 

 ford, Harvard, California Academy, and Philadelphia Academy. 



Host. — Quercus cliry sole/pis. 



Biology. — The flies were reared from a lot of galls (Hopkins U. 

 S. No. 15613&) which Avere supposed at the time of collection, April 

 18, 1918, to have all been those of a species of Disholcasins. When 

 these flies emerged July 15-August 1, 1918, they Avere at first thought 

 to be guest flies in the above gall whose maker does not emerge until 

 late in the fall. But these flies ha\e not at all the structure of guests 

 and the gall from which they came is therefore not recognized or 

 here described. 



Habitat. — The type locality is Camp Baldy, Calif. Paratypes are 

 from galls collected on the road from Holland, Oreg., to the Oregon 

 Caves July 21, 1922, the flies emerging about August 1. 



