No. 22,] HYMENOPTERA OF CONNECTICUT. 39I 



almost colorless ; radial area open, the vein bounding the areolet 

 on the posterior side exceedingly faint; abdomen smooth and 

 shining, subpetiolate, the terminal segments in museum specimens 

 almost entirely concealed under the second segment. 



The galls of this species occur on the under sides of the 

 leaves of Quercus bicolor, especially the late terminal leaves of 

 the hardy shoots of young oaks of this species. They are often 

 very numerous, as is shown by the fact that as many as two 

 hundred have been counted on a single leaf. When as numerous 

 as this, or nearly so, the galls are apt to be confluent. Usually 

 they are separate, about 4 mm, in diameter, including the woolly 

 covering, without which latter they are only 1-1.5 mm. across. 

 Each gall contains a single larva which is free and not enclosed 

 in a cell. In addition to the above description it may be said 

 that the galls are hemispherical and attached with the flat side 

 to the leaf, showing on the upper surface only as smooth, flat, 

 shining blisters. 

 *N. noxiosus Bassett. Noxious Oak Gall, 



Summer female* : length 2 mm, ; head black, finely and uni- 

 formly punctate; antennae 13- jointed, the first joint nearly black, 

 the second and third joints brownish yellow, the succeeding joints 

 merging gradually into dark dusky brown ; thorax microscopically 

 sculptured, without parapsidal grooves, scutel sculptured like the 

 mesonotum though somewhat coarser and without f oveae ; legs dark 

 shining brown, with yellowish brown joints, tarsi dark yellowish 

 brown ; wings hyaline, veins distinct and nearly all black, areolet 

 sharply defined, radial area open ; abdomen smooth shining black, 

 the ovipositor distinctly exserted. Male : diflfering from the vernal 

 femalef as follows: body longer than 1.75 mm,; antennae 14- 

 jointed, the third joint curved but not incised; legs clear yellow- 

 ish brown; abdomen small, and with a slender petiole. 



The summer galls of this species are large, woody, polythala- 

 mous, terminal or subterminal swellings on the twigs of Quercus 

 bicolor, varying greatly in size and form, but usually tuber-like 

 and three or four times as long as thick, the larger specimens 

 being nearly i inch in diameter and 4 inches long and containing 

 a large number of specimens of the insect. The smallest are almost 



* Female from summer galls. 

 + Female from vernal galls. 



