392 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



imperceptible swellings and have often but a single gall-fly in 

 them; these galls give rise to the females which live in the galls 

 over winter and come out before the leaves appear in the spring. 

 The galls just described are usually preceded in the spring by a 

 crop which affects the leaves only, and causes an enormous de- 

 velopment of the midvein, often to the extent of an inch in diam- 

 eter and an inch and a half in length. These latter galls are 

 smooth and green but irregular in shape, succulent and a little 

 harder than an unripe grape. The blade of the the leaf becomes 

 dwarfed and curled, and then after the galls mature it becomes 

 dry. In some seasons these galls are so abundant on certain trees 

 as to affect nearly all of the early leaves. The galls are filled 

 with larval cells from which are produced great numbers of both 

 sexes of the gall-fly about the 20th of June. Thus these latter 

 galls may be looked upon as the progenitors of the bisexual 

 generation of this species. 



New Haven, 24 January, 191 1 (A. B. G, B. H. W.). 

 N. (Dolichostrophus) irregularis Osten Sacken. 



Length 2 mm. ; head brown, mouth yellowish, antennae pale 

 yellow, third joint twice as long as the fourth, somewhat curved, 

 attenuated toward the base but stouter toward the tip, the fifth, 

 sixth and seventh joints almost equal in length ; thorax brownish 

 above, pale beneath, smooth and shining; legs pale, except the 

 tips of the tarsi, which are infuscated ; wings somewhat grayish, 

 radial vein almost parallel with the anterior margin, areolet dis 

 tinct, as are the cubital vein and the first transverse vein or basal 

 vein, the latter dark brown with a brownish cloud, the other 

 thick veins of a paler brown. 



The galls of this species were found on the leaves of the 

 white oak. 



N. perminimus Bassett. 



Female: length scarcely 1 mm.; head black, antennae 13- 

 jointed, mostly dusky brown ; thorax almost black, without parap- 

 sidal grooves, scutel somewhat roughened and without foveae ; 

 legs translucent brown but paler at the joints ; wings hyaline, 

 veins distinct, radial area open ; abdomen black. Male : head 

 dark, but not quite as black as in the other sex ; antennae 14- 

 jointed ; thorax highly polished and dark brown ; legs pale and 



