1864.] 593 



the knife than cut by it. 2.nd. Instead of the external surface being 

 phimp and of the natural texture of the bark of the twig, it was strongly 

 rugose, when recently gathered, and had much the color and texture of 

 a completely withered blue plum. This does not occur in green speci- 

 mens found at the same time of the year on the other two Willows, 

 though it is often seen in the old dry ones. — Length 1.00 inch, diameter 

 .80 inch, external buds 3. One specimen. 



Larva. — The larva found in the S. oordata gall with recurved beak August 1 

 was .06 inch long, bright opaque orange with a ventral and dorsal semitranslu- 

 eent, polished, broad, orange vitta, and the breast-bone indistinct. A very 

 large specimen from S. humilis examined November 15 was bright sanguineous 

 with yellowish bowel-like markings and the breast-bone as in all the preceding 

 species, except that, as in six others examined November 2], viz: 3 from S. hu- 

 milis and 3 from S. cordata, the former .13 — .17 inch and the latter .17 — .19 inch 

 long, it was stouter and blacker, and the two anterior horns of the Y were only 

 J as long as the posterior part. This seems to be the prevalent variety in this 

 species, none having hitherto occurred that varied vice versa, as in all the pre- 

 ceding species, though one or two have occurred witli the 3 arms of the Y sub- 

 equal. Length .23 inch, breadth .07 inch. I have occasionally found speci- 

 mens both of C. ,s. brassicoides and C, s. strobiloides which were similarly elon- 

 gated not temporarily but permanently; but in this species they are always 

 so. Another specimen from S. humilis examined February 26, was orange-co- 

 lored, and another from the same willow on March 21, was pale sanguineous 

 orange freckled with bright sanguineous and .18 inch long. By November 

 almost every larva had made its cocoon, which is described under the head of 

 the Gall. The larva obtained in November from the gall on S. discolor was un- 

 distinguishable from six specimens found at the same date in galls from the 

 other two willows, except that the breast-bone was larger, blacker and full ^ 

 more robust, being nearly as broad as long, instead of A as broad as long. I 

 have, however, since noticed that specimens of C. s. strobiloides. <fec.. occasionally 

 occur which vary in the same manner from the normal type, i. e. in having a 

 much more robust breast-bone. 



Pupa. The first pupa (from S. humilis) was found April 12. It 

 did not diflPer materially from any of the preceding, but the pupal in- 

 tegument (7 specimens) differs most remarkably from those of all my 

 other Cecidomyia in the whole of it, except the abdomen, being strongly 

 tinged with fuscous. It would be interesting to know whether Dr. 

 Fitch's species has the same peculiarity. The pupa makes its exit 

 through the terminal beak of the gall, forcing its body halfway out of 

 it and there transforming, or sometimes falling entirely out. Length 

 (from the pupal integument) .17 — .19 inch. The pupa from the galls 

 on 8. cordata and S. discolor I do not know. 



