NORTH AMERICAN HYMENOPTERA. 71 



and rather thick shelled and filled with fine silvery white hairs that 

 radiate from the single larval cell that is attached to the base of the 

 gall. 



From several thousand galls I have reared less than fifty gall-flies. 

 These are all females, and are described as follows : 



Gall-flies. — Head black, face and vertex finely punctate, and with a few mi- 

 croscojiic hairs; antennje stout, fourteen joints, first thick, second less thick and 

 only two-thirds as long, third fully as long as the two preceding taken together, 

 fourth one-half as long as the third, the remaining ones short, all black and with 

 short, inconspicuous hairs. Thorax black, niesonotum polished and shining, ex- 

 cept the very distinct parapsidal grooves and a small hairy spot in front of the 

 base of each wing; scutellum opaque, rough, foveai present, rough like the rest 

 of the scutellum. Abdomen bright, shining black. Legs black, with very dark, 

 brownish red joints, the whole having, in a certain light, a reddish hue; ungues 

 simple. Wivgs large, hyaline ; veins slender, the areolet very small, the cubitus 

 colorless the entire length, the radial area long, open and quite narrow. Length : 

 l>ody, .10 inch. ; antennae, .10 inch. ; wings, .18 inch. 



4. D. siniilis u. sp. 



Galls received from Mr. Siler and collected by him in southern 

 Utah. They are in all respects, save color, like those of J., ehurnem 

 Bass., but the color is a shining brownish buff. They are found on 

 a different species (or variety) of oak. 



'J'he gall-flies also resemble A. ebiirneus, but are much smaller, the 

 body being only .08 inch., the wings .12 inch, and the antennae .07 

 inch, in length, and the cubital vein in the lower half is subob-solete. 



A large number of specimens may show this to be only a vai'iety, 

 but the difference in the length of the wings and the antennte, if 

 constant, seems too great to be merely varietal. There may be sea- 

 sonal difl^erences, but as to this I am not informed. 



5. D. corrugis n. sp. 



Among a hundred or more of gall-flies captured last spring, while 

 in the act of ovipositing in the buds of several species of oaks, 

 were several distinct species, and one of these taken from the buds 

 of Q,. prinoides, produced, so far as my observations went, no galls 

 whatever, none being found in any of the several visits I made these 

 bushes during the summer. 



Since the discovery, last spring, by Miss Cora A. Clarke of two 

 new species, — Andricus Clarkei and A. pidchra, and of Neuroterus 

 pallldus by myself, all on the aments of different species of oak, I 

 have come to the conclusion that the insects in (^[uestion are the aga- 

 mous females of another bisexual species that comes from galls on 



