H02 [December 



hibit the longitudinal slit made by the ovipositor of the mother Saw-fly. The 

 smallest galls above referred to are only .15 inch in diameter; but there is a 

 regular gradation from these to the larger and more conspicuous forms, and by 

 isolating a number of the first in a separate breeding-jar, I ascertained that 

 they produced the same Cecidomyia (7 specimens April 7 — -May 1(1) and the 

 same 3 parasites, viz. 2 Chaleidides and 1 Proctotrupide. When cut into about 

 the last of July, the interior of this gall to the depth of .07 — .10 inch from the 

 surface, is found to be white and fleshy; when cut into in the autumn or early 

 in the spring, the substance of all but the very smallest, which are almost en- 

 tirely woody and whitish, is found to be reddish-brown and of a dense, spongy 

 texture, with indistinct fibres radiating from the twig. Some little distance 

 from the external surface there are at this time a number of cells, about § of 

 them tenanted by white, parasitic larvae, some hairy and some glabrous, be- 

 longing to the Chalcididous genera Callimome and Decatoma (?), and about J of 

 them tenanted by the orange-colored larvse of the Gall-gnat which originates 

 the gall. In 3 or 4 instances I have seen the gall S. gnaphalioides growing ses- 

 sile from the tip of (S. batatas. — Described from 100 — 150 specimens. Very com- 

 mon near Eock Island on S. humilis. 



In galls similar to the last mentioned, small, elongate-oval galls, but 

 growing on S. cordata. I found May 9 a larva undistinguish;ible from 

 that of C. s. batatas and with the same breast-bone, but did not suc- 

 ceed in breeding the perfect Grall-gnat. though I obtained many Chal- 

 cidiffpe from these galls identical with two species bred copiously from 

 S. batatas, one of which — a Decatoma ('^) with spotted wings — has 

 hitherto occurred in no other gall, though a similar species infests Ci/- 

 nips q. spongifica and other gall-flies. 



In November I found on *S'. discolor 8 galls, apparently identical 

 both externally and internally with the iS. batatas found on S. humilis, 

 8 old and dry ones of the normal form which were all bored and strung 

 along on the same twig, and 5 green and recent ones of the lateral, 

 bunnion-like type on two diffbrent twigs. Their diameter was .19 — .40 

 inch. From the recent ones I obtained 6 larvae, which when compared 

 with 6 taken from galls on S. humilis differed in no respect. In the 

 preceding spring I had obtained 2 or 3 similar galls of the bunnion-like 

 type from the same bush, from which I bred a large Microijaster, whence 

 I infer that some lepidopterous larva had been living as an Inquiline 

 in one of them, as the parasite was much too large to have lived in the 

 body of C. s. batatas, and besides I have met with no instance of Ich- 

 neumonidous insects being parasitic on Cecidomyia. I found at the 

 same time several galls on the same bush, which, as has been stated to 



