NORTH AMERICAN HYMENOPTERA. 77 



minal galls are an inch in diameter and shaped like a strawberry. 

 The others are about half as large, and of the same shape. All are 

 more or less uneven on the surface. These are all old galls and the 

 outer bark has mostly fallen off, and the entire surface is dotted as 

 thickly as possible with very small, open larval cells. The larger galls 

 must contain, each, several hundreds of these teuantless cells. The 

 cells are distinct from the woody fibre in which they are imbedded, 

 but cannot be separated from it. The galls are easily taken for those 

 of A. scitula Bass, and such I took them to be until I found that the 

 insects were very diflferent. ^4. semmosus is a much smaller insect 

 than A. scitula. 



Opening some of the galls I found several gall-flies, but not one 

 of them is perfect in all its parts. I have the abdomen of one, the 

 thorax, legs and imperfect wings of another, and the head and an- 

 tennae of still others, and from these I gather the following charac- 

 ters : 



Gall-flies all females. — Head black ; antemife short, dark honey-yellow, four- 

 teen joints, the first and third equal ; from the fourth to the thirteenth very 

 short, the thickness even exceeding the length, the fourteenth longer and cone- 

 shaped ; mesouotum black, finely punctate, 7iot hairy, the parapsidal and inter- 

 parapsidal parallel lines exist as faint, hardly discernible depressions ; the dorsal 

 or median line indistinct, but extending more than half way to the collare ; a 

 short, deep depression over the base of each wing ; scutellum shining, but irregu- 

 larly and coarsely wrinkled. The shining fovese are very deep and separated 

 by an unusually high, narrow ridge. Abdomen black and shining, excej)t the 

 posterior margins of the terminal segments, which are yellowish brown. Legs 

 dark reddish brown, ungues simple. Wings so crumpled that a good description 

 cannot be had, though the veins are faint and the areolet subobsolete. Length 

 of the body .10 inch. 



It differs particularly from A. scitula, the only species that it can 

 be taken for, in having very large, deep, shining fovese, while A. 

 scitula has none, and in the fourteen antennal joints and the coarsely 

 wrinkled scutellum. 



I collected the galls in Rockport, Ohio. 



7. A. (C'allirhytis) pilula n. sp. 



Small, round, thin-shelled galls on the blade of the leaves of Q. 

 undulata, collected in southern Utah by Mr. Siler. They are usually 

 situated near the margin of the leaves and always on one of the 

 principal leaf veins, and project equally above and below the surface. 

 The average size is only .15 of an inch in diameter. The gulls re- 

 semble those of Nenroterus ntricula Bass, more nearly than any other 

 species known to me. 



