o06 [December 



A. maklis they only attain the origin of the 1st discoidal vein; yet in both, 

 the proportions of the different joints ;ire essentially the same. 



Setting aside these structural differences, it seems unnatural to place in 

 the same genus two insects whose habits are so totally distinct as those of 

 P. jjopidiraidis Fitch and P. pyrl Fitch. The more natural our systems 

 of classification become, the more are insects of dissimilar habits grouped 

 under different s;enera. 



Byrsocrypta pseudobyrsa n. sp. — Pale obscure greenish, pruinose. Antennse 

 sometimes obfuscated, always with the 6th joint unguiculate. Thorax blackish, 

 pruinose. Joints of abdomen with obscure fuscous fasciae. Legs with the tarsi, 

 and sometimes the tips of the femora, obfuscated. Wings whitish, subopaque, eosta 

 and stigma yellowish; veins hyaline except the costals which are pale yellowish- 

 brown, the subcostal generally blackish at base and black at the stigma but not 

 thickened there. Hind wings with all the veins hyaline. Length to tip of wings 

 .I'O— .13 inch. 



Six specimens. The antennte scarcely attain the base of the 1st dis- 

 coidal of the expanded wing, and the stigma is about three times as long 

 as wide and very acutely pointed at its basal end. Forms near the middle 

 of the midrib of the leaf of the cotton-wood (populus angulata) what ap- 

 pears above as a smooth, green, semicircular, compressed gall, crowned by 

 the midrib, and from one-quarter to two-fifths of an inch long, but which 

 below is entirely open, the sides of the leaf bending down together so as 

 tu touch each other and conceal the opening. The insects often wander 

 from this false gall and associate with Aphis po^ndifoUse, Fitch. Comes 

 very near popularia Fitch, (the gall of which is unknown,) but that spe- 

 cies has the discoidals "blackish" and the ''antennae only f the distance 

 to the wing-sockets." Differs from itopall-ijlohuU and populivense. Fitch 

 in the subcostal not being thickened at the stigma, and also in the pecu- 

 liar structure of its gall. 



The recent larva is densely covered with white pruinescence, on remov- 

 ing which it is yellowish, with only the eyes and the tarsi blackish, and 

 the disk of the abdomen freckled with reddish. 



Byrsocrypta vagabunda n. sp. — Black, polished, with no appearance of pruines- 

 cence. Antennse and legs dull fuscous. Abdomen and venter obscure opaque- 

 yellowish, varied with fuscous or sometimes with brown. Wings subhyaline with 

 a whitish tinge, costal and subcostal veins and one-third of the inner edge of the 

 wing from the tip of the 1st discoidal to the base of the wing, conspicuously fus- 

 cous; the remaining veins in both wings whitish hyaline; costa slightly tinged 

 with brown, stigma pale fuscous-browu, its interior vein thickened. Alar ex- 

 panse .43 — .-A inch. 



Fileven specimens. The 6th joint of the antenna) is two-thirds as long 



