6 PROCEEDINGS OF THE KATIONAI. MUSEUM. vol. (Jl. 



posite middle of eyes, interociilar space .55 transfaciul and area l.-i 

 times as broad as high, malar space half eye with groove and parallel 

 stria to mouth, low median ridge on face above clypeus, antennocular 

 space less than ocellocular, palpi 5- and 3-segmented, antennae 14- 

 segmented, lengths of first four as 16:7:17:12, 5-13 gradually 

 shorter, last about 1.5 times preceding, distal third not more slender. 

 Mesoscutum wider than long, shining, feebly coriaceous, with scat- 

 tered hairs, parapsidel grooves deep, smooth, precurrent. their sepa- 

 ration behind at least one tenth width of head, anterior and lateral 

 lines faint. Scutellum rugoso-punctate with two large smooth pits 

 at base. Carinae on propodeum bowed out, inclosing a space wider 

 than high with trace of a median ridge in some specimens. Hind 

 tarsus shorter than tibia, second distinctly shorter than fifth, claws 

 simple. Wings hyaline, second abscissa of radius angled and 

 slightly clouded, not longer tlian apical part of subcosta. areolet 

 reaching one-fifth and cubitus two-thirds way to basal, surface 

 pubescent, margin ciliate. Abdomen compressed, longer than broad, 

 second tergite occupying .7 and with a transverse row of hairs across 

 middle. Ventral valves protruding obliquely, ventral spine at least 

 3 times as long as broad. Ovipositor when dissected out 1.2 times 

 as long as antenna. Using width of head as base tlie length of meso- 

 notum ratio is 1.1, antenna 2.0, ovipositor 2.2-2.4. wing 3.4. 



Length of 25 pinned specimens 2.4-3.1 mm. Average 2.8 mm. 

 The 19 males including the types measure 2.7-3.3 mm. Average 

 3.1 mm. 



Later 44 other adults, determined as this species, were found in the 

 Hopkins collection (Hopkins U. S. No. 12561). They were from 

 Ashland, Oregon, reared from acorns of califomica of the 1914, crop. 

 collected by P. D. Sergent on September 5. 1914. Unfortunately no 

 acorns were preserved, but the adults were said to occur "in gall 

 pockets on the inner surface of the acorn shells " and 8 were obtained 

 from three acorns. The flies emerged September 5-October 7, 1914. 

 They are larger than those from the smaller acorns of the other two 

 species of oak. The 29 females range from 2.8-3.7 mm. Average 

 3.3 mm. The males range from 3.0-4.2 mm. Average 3.8 mm. 



Host. — Quercus agnfolia Nee, Qtinr-m vnsUseni A. de Candolle, 

 and Quescus califomica Cooper. 



GfiU.—T\\Q gall produced by this species is underscribed. Separate 

 woody cells are produced in the acorns, which are somewhat distorted 

 in shape and usually under normal size (fig. 1). They are always 

 in the lower third of the acorn and the cell is adherent to the wall of 

 the acorn and not separable from it, projecting slightly into the 

 interior cavity, which has a velvety lining and may contain traces 

 of the cotyledons. An acorn may contain from one to half a dozen 



