00 H. F. BASSETT. 



towards the end ; first and second joints sliort, globose, the third very slender; 

 the rest gradually thicker to the last. Thorax black, less shining and more 

 coarsely crackled than in the male; the parapsidal grooves less distinct, and the 

 scutellum less smooth than the male. Abdomen black, shining; the second seg- 

 ment longer than the remaining ones, but not concealing them. Leqs dark 

 brown, with paler joints. Wings hyaline, with the steel reflections noticed in 

 the male ; veins more distinct, areolet small, generally but not always present; 

 radial area broader and shorter than in most of the gall-making Cynipidge; the 

 ovipositor is often seen fully exserted in the dry specimens, and is four or five 

 times the length of the body. Length : body, .08 inch. ; wings, .08 inch. ; an- 

 tennte, .05 inch. 



As other oaks of this species in this vicinity yielded no galls of 

 this sort it may be that this colony is sporadic, and that its true 

 habitat has not been discovered. 



2. N. pallidum u. sp. 



Galls in dense clusters at or near the end of the anients of Q. 

 bicolor, but seldom found on the basal half of the flower stems. It 

 is safe to call them monothalamous, thoug-h now and then a ffall is 

 found that contains two larval cavities. The galls are of a fine, soft 

 cellular consistence, easily crushed in the fingers, and contain no 

 separate larval cell. They are of a pale, faded wood color and 

 smooth, and unevenly globular. They seem to be free from the at- 

 tacks of parasites, for among thousands of galls I fail t(5 find a single 

 one. 



The flies mature earlier than the two s})ecies already described 

 as found on the sterile flowers of the oak, for, when found, the insects 

 had gone with the exception of a few belated ones, from which I have 

 made the following description. They are of both sexes. 



Gall-flies. — Female. — Head, except the dark eyes, almost colorless in some 

 specimens, or at most of a pallid yellowish brown, and in others dark brown to 

 a shining black on the vertex. Legs and the first three joints of the antennse 

 same color and semi-transparent; antennje thirteen jointed, the first and second 

 not differing much in form and size, both rather large, third long, pale, remain- 

 ing changing gradually to a dusky brown ; mesothorax smooth, shining through- 

 out; scutellum also smooth and shining, fovete wanting. Le^fs almost colorless, 

 except a slight brownish tinge in the femur ; ungues black, simple. Abdomen 

 black, the diameter from the dorsum to the venter considerably more than the 

 length. Wings large, hairy, veins dark and distinct, areolet of medium size, 

 cubitus slender and reaching quite to the first transverse, radial area long, nar- 

 row, open. Length : body, .06 inch. ; wings. .08 antennse, .05 inch. ; these meas- 

 urements are from dry specimens and probably rather too small. 



Male throughout of the same pallid hue seen in the antennae, and legs of the 

 female; antennte fifteen jointed, otherwise as in the female. Abdomen small, 

 briefly petiolate and the posterior dorsal portion darker than any other part of 

 the body. Wings do not diff'er from those of the female. 



