No. 22.] HYMENOPTERA OF CONNECTICUT. 413 



*A. cicatricula Bassett. 



Female : length 2.5 mm. ; head and thorax practically as in 

 the male ; antennae 13-jointed, abdomen shining black, except 

 beneath, where it is clear translucent brown, sheaths of the ovi- 

 positor extending above the dorsum ; legs all dark reddish brown ; 

 wings as in the male. Male : length nearly 2 mm. ; head black, 

 vertex microscopically netted, antennae 15-jointed, first and second 

 joints dark reddish brown, remainder light yellowish brown, shin- 

 ing, first joint heavy, second ovoid, third one-fourth longer 

 than the first two combined and slightly curved but scarcely in- 

 cised, fourth to fourteenth subequal, and each as long as the first 

 and second combined, apical joint conical ; thorax black and 

 shining, mesothorax rounded and with regular transverse reticu- 

 lations, two faint parallel lines present, parapsidal grooves entire 

 and almost parallel, converging only slightly toward the scutel, 

 which is finely rugose and has f oveae that are shining ; legs with 

 the posterior pair dark brown and with pale sutures, the anterior 

 and middle pairs light reddish brown, claws with two teeth ; 

 wings hyaline, first and second transverse and submarginal veins 

 brown, the remaining veins entirely or almost entirely colorless, 

 areolet present, radial area open, cubitus becoming obsolete half- 

 way toward the first transverse vein ; abdomen with its second 

 segment nearly round, polished and black, only the edge of the 

 remaining segments visible. 



The galls of this species are polythalamous, occur on the mid- 

 vein of the leaves of Quercus alba, one to a leaf, are situated at 

 times at the base but usually from one-fourth to one-half the way 

 beyond the base, rarely above the middle, project one-third below 

 and two-thirds ^bove the surface of the leaf, and are rounded on 

 the under and cone-shaped on the upper surface of the leaves. 

 The gall is solid and somewhat fibrous, its shortest diameter meas- 

 uring 12.5 mm. and its longest diameter from 15 to 21 mm. The 

 larval cells radiate in all directions from the centre of the gall 

 and are quite numerous. There is at or near the centre of the 

 cone a small scar or indentation which is invariably present. 

 *A. corniger Osten Sacken. Horned Knot Oak Gall. 



Female : length nearly 3 mm. ; mostly black ; head as broad as 

 the thorax, face finely and indistinctly pubescent, irregularly 



