590 [December 



where this species — S. nigra — grows promiscuously intermixed with S. 

 Idngifolia or with S. eordata, I have in vain hunted time and again for 

 them, both in the summer and in the winter, when they could be seen 

 with the greatest ease, even if they were only half the size of S. (jiut- 

 phaJioi(h')(. But for this fact, and the further fact of S. humilif< bear- 

 ing; two distinct galls of this peculiar type, we might, from the great 

 similarity of their insects, both in the larva, pupa and imago states, 

 infer that they were all of them merely what I have called Phytophagic 

 Varieties, instead of being specifically distinct, and each confinirg them- 

 selves to their appropriate species of willow. 



Larva. — Undistinguishable from that of (J. s. ht'assicoides ; breast- 

 bone identical and with the same variations. Length .12— .15 inch, 

 width .06 — .07 inch. Three specimens. The cocoon is of the usual 

 thin, delicate texture, whitish and about as long again as the larva. 



Pupa and imaCxO unknown. 



No. 7. Gall S. cornu. — On S. humilis. A lateral bud deformed into the shape 

 of a monothalamous. very elongate, slender, cylindrical, tapering, hollow, rigid 

 horn, very slightly pubescent, of a very dark reddish brown color when ma- 

 ture, and with about 12 or 14 longitudinal, pretty regular striae like a coleop- 

 terous elytrum. This gall is .?>0 — .77 inch long, .07 — .10 inch in diameter at 

 base and .05 — .07 inch close to the tip. where for the length of about .10 inch 

 it is flattened and moderately pubescent, and at the extreme tip, which is 

 rounded, opens by a terminal slit. Sometimes it is solitary, sometimes 2 or '■', 

 of them, or even as many as 10, grow at irregular intervals on a small twig 4 

 inches long, with a few of the intervening buds in their normal condition. Ge- 

 nerally it is perfectly straight, diverging upwards from the twig at an angle of 

 15° — 35°, but occasionally it is a little bent in the middle, and occasionally it 

 curves backwards in a regular curve, so that in one instance the tip nearly 

 touches the base. When cut into, the walls of the hollow are seen to be no thicker 

 than stout paper, but very stiff" and hard, and on the terminal h the internal 

 surface is jjretty smooth with indistinct longitudinal rugae, except the terminal 

 .05 inch, which is armed with very long, whitish pubescence directed obliquely 

 forwards. In the basal i of the horn lies the cocoon, which is closely aggluti- 

 nated to the walls of the cell except at its tii?, where it forms a filmy, whitish 

 diaphragm as in S. siliqua n. sp. ? The cell formed by the hollow of the de- 

 formed bud is prolonged into the woody origin of the bud for .10 — .15 inch, but 

 the twig itself is not swelled or deformed, as it is in the allied polythalamous 

 gall S. triticoides n. sp., further than by a slight and scarcely noticeable intu- 

 mescence at the origin of the bud. 



Described from 8 living specimens on four difierent twigs and 10 old 



dead and dry specimens all on one twig, the whole gathered in Noveni- 



