334 AMERICAN HYMENOPTERA. 



was solved. These galls are so small and succulent that they soon 

 shrivel up and disappear. When once found it was easy to discover 

 them in considerable numbers, but even now I fail to detect them 

 among bunches of dry Andricus galls. 

 The flies are described as follows : 



Female. — Head large. Antennae thirteen jointed, first large, ovate, second 

 much smaller, third equal to the first two, they are of uniform length, very 

 short, color clear, semi-translucent brown, all except the first two very slender 

 and easily broken, and often presenting a shrunken appearance. Thorax rela- 

 tively large, polished, very black, the surface is rumpled owing to its extreme 

 thinness, no two specimens being alike in this respect. Scutellum small, rounded, 

 shining black, as is also the transverse groove at its base, this groove is large and 

 incurved. Abdomen small, black, less brilliant than the thorax, triangular 

 through the retraction of all the segments within the first. Legs dark, clear 

 brown but paler at the joints. Wings large, smoky and hairy: veins large and 

 strong. Areolet large. Cubitus reaching quite to the first transverse. Radial 

 area open. By a curvative in the second transverse at the base of the areolet, 

 the outer angle is acute and the inner a right angle. In most of the species of 

 this genus they are both right angles. Body .06, antennae .04, wings .07. 



Male. — Black, except the antennae and legs. Antennae fifteen jointed, all clear 

 brown and very frail and slender, except the first two. Legs same color as the 

 antennae though a little paler at the joints. The whole insect frail and delicate. 

 The abdomen long pedicellate, shining brown. Wings as in the female. Body 

 .06, antennae .05, wings .07. 



Neuroterus Oillettei n. sp. 



Gall. — A pustule like enlargement of the petioles and mid-veins 

 of the leaves of Quercus obtusiloba. Polythalamous and quite 

 irregular in size and form. 



My dry specimens are much shrunken and distorted. 



Gall-fly. Male. — Head black. Antennae fourteen jointed, first joint short and 

 obscure, brownish, second large, ovate, almost colorless, third long and slender, 

 all except the first joint more or less translucent, fourth to the fourteenth very 

 short. Thorax rounded, shining black. Parapsides— as in all of this genus — 

 wholly absent. Scutellum beautifully polished, black, separated from the meso- 

 notum by a broad, shining groove. Abdomen petiolate, petiole pale or colorless, 

 following segments dark. The abdomen is small and triangular. The legs are 

 nearly colorless. Wings large, hairy and somewhat dusky: veins all very dis- 

 tinct, yellowish brown. Areolet large. Radial area long, open. Cubitus reaches 

 in full size to the first transverse veiu. Body .05, antennae ?, wings .07. 



Female. — Antennae thirteen jointed. Abdomen smaller than is usual in the 

 females of this genus. No petiole. Legs pale, with shining, translucent brown 

 in the middle of the femur and tibia. The female measures the same, even in 

 the wings. 



Named for Prof. C. P. Gillette, of Fort Collins, Colorado, whose 

 studies have so greatly augmented our knowledge of American 

 Cynipidae. 



