110 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 68 



Vertex coriaceous with scattered punctures. Cheeks broad- 

 ened behind eyes. Malar space .56 eye, radiating ridges above 

 mouth. Antenna 14-segmented, lengths as (scape) 17 (width 

 7) : 8(5) : 16(4) : 10: 10: 10:9: 9: 8: 8: 8: 7: 7:11(4). Pronotum 

 " broad," one-fifth as long in middle as on sides, rugoso-punctate. 

 slightly pubescent. Mesoscutum broader than long, with discon- 

 tinuous sharp transverse ridges, the intervals rather smooth and 

 shining; parapsidal grooves narrow, percurrent, crossed by the 

 ridges anteriorly, the enclosed area rounded behind, no median; 

 anterior and lateral lines fine but distinct. Scutellum rugose, disk 

 faintly margined behind, no distinct pits at base. Carinae on pro- 

 podeum broad, straight, diverging above. Hind tibia longer than 

 tarsus whose segments are as 36 : 14 : 8 : 5 : 13, claws simple. Wing 

 hyaline, pubescent and ciliate, radial cell open, twice as long as 

 broad, first abscissa of radius arcuate, one-third length of second, 

 which is slightly curved, areolet reaching one-fourth, cubitus three- 

 fourths way to basal and if prolonged would reach it slightly below 

 the middle ; veins brown. 



Abdomen as long as head and thorax, length to height to width 

 as 36:25: 18, petiole stout, sulcate, second tergite bare, highly pol- 

 ished, longest on median dorsal line, pointed behind, slightly crackled 

 under high magnification near tip, other tergites hidden. Hjq^o- 

 pygium long but not conspicuous, ventral spine almost bare, in side 

 view three times as long as broad. Using widtli of head as a base 

 the length of mesonotum ratio is 1.1, antenna 1.7-1.9, wing 2.8-3.0. 

 ovipositor 2.9-3.1. 



Length, 2.7-3.8 nun. Average of 77 pinned specimens, 3.2 mm. 



Male. — Similar to female in coloration and sculpture. Antenna 

 15-segmeiited, first five segments as 15:8: 17 : 9 : 10, third as stout 

 as the second and strongly curved. Abdomen shorter than head 

 and thorax. 



Length, 2.2-3.8 mm. Average of 36, 2.9 mm. 



Type.— C&t. No. 27224, U.S.N.M. Type female, allotype, 15 male 

 and 30 female paratypes. Paratypes at American Museum. Field. 

 Stanford, Harvard, and Philadelphia Academy. 



Biology. — The type is selected from a series reared March 17, 

 1923, from the large abrupt woody stem galls of Andricus rur/inosus 

 Bassett collected at Magdalena, N. Mex., the previous October 

 on Quercus grisea. Paralype material reared April 6 from the 

 same species of galls collected in the Santa Rita Mountains, Ari- 

 zona, on Quercus ohJongifolia. Paratype material also reared from 

 the same galls collected in Tumacacori Mountains, Arizona, on 

 Quercus arizonica. The flies issued March 8 and April 5 and 20. 



