NORTH AMERICAN HYMENOPTERA. 85 



I have collected these galls in northern Ohio and in St. Lawrence 

 County, N. Y., and have received specimens from Mr. C. P. Gillette 

 that were found in Michigan and Iowa. Those collected by myself 

 grew on Q. macrocarpa. 



2. .4. politus u. sp. 



Gall-flies. — Entire insect black. Head smooth, shining; antennfe with four- 

 teen distinct joints; first large, club-shaped, second oblong-ovate, third as long 

 as the first and second taken together, fourth two-thirds as long as the third, 

 remaining ones rather short. Thorax very small, smooth and shining: scutellum 

 minute, short and apparently without fovea"; the usual rudimentary wings are 

 absent. Legs brownish black and shining, except the tarsi, which are dusky and 

 nearer brown than black. Length .07 inch. 



Two specimens sent me by Dr. C. V. Riley, who received them 

 from J. G. Barlow, of Washington County, Mo. I have no galls, 

 and am not informed whether they were captured at large or reared 

 from galls. 



It is the smallest species known to me, and is closely allied to the 

 genus Biorhiza. 



AMPHIBOLIPS Eeinh. 

 1. A. C'aroliniensis n. sp. 



The galls belong to the oak-apple family, and much resemble those 

 of A. sponglfica O. S. and A. eocinncB O. S., but the surface is more 

 coarsely reticulated and less glossy, and intei'nally the spongy mass 

 surrounding the larval cell is of a much darker color. The shell is 

 also much thinner, and, in my dried specimens, is irregularly shrunken 

 and depressed, until they look like pressed figs. 



I am not sure as to the species of oak on which they grew, but the 

 few immature leaves that came with the galls seem to be those of Q. 

 obtusiloba. The galls are attached to the midvein near the base of 

 the leaf and prevent its development beyond the point of attach- 

 ment ; they are as large as those of A. spongifica, and differ widely 

 from A. chierea described by Mr. Ashmead. 



The single female gall-fly in my collection very closely resembles 

 the two scarcely separable s{)ecies just mentioned, but the head and 

 thorax are black, while in those they are very dark brownish red. 

 The parapsidal grooves are scarcely recognizable in the sculpturing, 

 which is coarser than in the two species just named. The legs are a 

 shade darker than the clear reddish brown of those and the abdomen 

 has the same shining reddish brown, but the second segment is con- 

 .siderably shorter than in those. The wings are a shade less fuscous, 

 the first transverse vein more distinctly defined, and the dark cloud 

 in the base of the open radial area smaller and not involving the 



