S pisum, n. sp.
On Salix discolor
A subspherical, pea-like, hollow, pale yellowish-green gall, always growing on the under side of the leaf. and almost always from one of the side-veins, very rarely (1 specimen) from the midrib, and attached to the leaf by only a minute portion of its surface, .18 — .28 inch in diameter, and a few, which were probably immature or abortive, only .08 inch in diameter. Almost invariably there is but one gall to one leaf: but on 4 leaves there were two, and on 2 leaves three of them, and occasionally two are confluent. The surface of the gall is without pubescence, in some smooth and even, in others a little shrivelled, generally studded in the medium-sized ones with 4 — 12 small, robustly conical nipples, which in the larger ones have hurst into a scabrous brown scar. Only in 3 out of 62 galls was there any rosy cheek, as in S. pomum. The point of attachment is marked on the upper side of the leaf by a brown sub-hemispherical depression about .04 inch in diameter. Abundant but local. Described Aug. 25 from 62 freshly-gathered galls. At the time the 1st part of this Paper was published I was unacquainted with this gall, which accounts for the irregularity in the numbering, (21 bis.)
On the same bush with the above there occurred 13 galls, mostly unbored, so identical in appearance with S. pomum that I did not think it worth while to attempt to breed from them. On Oct. 14, out of another lot of S. pisum on another bush of S. discolor, I found that about one-fourth to one-fifth had a slightly rosy cheek. On this bush also I met with 4 S. pomum in company with S. pisum. but all empty and bored, but whether bored by the Gall-maker or by the inquilinous Anthonomus sycophamta. n. sp. (Coleoptera) is uncertain. In both the above two cases a few S. discolor bushes were growing in the midst of very large numbers of S. cordata [eriocephala], the species on which S. pomum is normally found. This gall is evidently allied to those produced by the European Nematus intercus and N. gallarum, which are described as "globose, spongy, pedunculated galls along the mainrib of the leaf;" but it differs in growing, not exclusively from the mainrib, but indiscriminately from any of the veins. Distinct from S. pomum by its being peduncled not sessile, and by its smaller size and the general absence of a rosy cheek, and from S. desmodioides by its short peduncle and by its very different shape.
