S. strobiliscus. n. sp.

On S. rostrata [bebbiana], a high northern willow not found near Rock Island. I only know this species from a single dried and mature specimen received from Mr. Bebb. and gathered in Winnebago Co., on the extreme northern border of Illinois. It has a diameter of .70 inch and differs from S. strobiloides O. S. 1st. In the tips of all the leaves on the outside of the gall, and not merely those towards the tip of the gall, being angulated not rounded. 2nd. In their external surface not being so strongly pubescent, especially the portion lying "to the weather." 3rd. In the leaves at the tip being almost linear or parallel-sided instead of oblanceolate, and proportionally about 1/2 longer so as to project in a kind of beak from the tip of the gall. 4th. In the tip of the gall being more open than is usual in S. strobiloides. 5th. In the veins even on the inside of the leaves being subobsolete. The cocoon, as far as can be judged from what remains of it, was similar to that of S. strobiloides, but unfortunately it contained, not the larva or pupa of the Cecidomyia, but a parasitic Callimome, which infests several of these Gall-gnats, in the imago state. Hence, and from the fact of there being catkins in flower on the twig on which it grew, we may know that the specimen was about 10 or 11 months old when gathered. As usual in mature S. strobiloides, the twig on which it grew had been killed immediately below it for the space of h an inch or so. Since it might possibly have been the case that it was this species, and not my S. strobiloides, which was named strobiloides by Baron Osten Sacken, as he merely describes his gall as being "in the shape of the cone of a pine and an inch or more long," I communicated to him the distinctive characters between the two species, and he has been kind enough to inform me that my S. strobiloides is identical with his. The specimens which he originally used were obtained in Northern Illinois, and he tells me that he afterwards gathered a single one in Massachusetts, so that we know of this one gall, at all events, that has a wide geographical range.

Larva, pupa and imago unknown.

Cecidomyia salicis strobiliscus Walsh

I described this gall from a single dried specimen found by Mr. Bebb on Salix rostrata [bebbiana] in North Illinois. I have since found very numerous specimens of what for the present I regard as the same gall on S. discolor near Rock Island, IL. Of 23 gathered March 23d one was undistinguishable from the S. rostrata gall; the rest had the tips of the external leaves (except at the tip of the gall) not angulated, but more or less rounded with a subobsolete midrib outside which terminated in a minute tooth or beak. In other respects they did not differ, and especially in the veins on the inside of the leaves being obsolete or subobsolete. The general outline of this gall was ovate lanceolate, rarely ovate ; length — rejecting one stunted specimen, which however contained a larva — 1.05 — 1.G5 inch, diameter .57 — .72 inch. The stunted specimen was not porrect, but deflected at an angle with the axis of the twig, and I subsequently found a few others varying in the same way. In one gall I met with 2 or 3 of the same Orchelimum eggs which occur so copiously in S. strobiloides 0. S., and May 26th I bred several Orchelimum larvae from these galls.

Rabdophaga salicisstrobiliscus

Host: Salix discolor, rostrata [bebbiana]

Salix
Bud gall comprising many modified leaves
Leaves generally appressed, imbricate, simulating a pine cone
Leaves triangular, narrowing toward tip to produce an open “beak,” or twig recurved below gall
Tip of gall beaklike; twig beneath gall not recurved

The original reporter of this gall (Walsh 1864) suggested that it might only be an aberrant form of that formed by R strobiloides

[No drawing is given for this gall]

Range: IL

[Note referring to this and several other bud gallers]: Leaves of these galls are typically largest on the outside of the gall but narrow considerably toward the center of the gall. In this key only the outer leaf shape of the mature gall is described. The gall formers are always at the heart of the gall, surrounded by linear leaves. The larva feeds upside down and reverses position before pupation. The gall makers have one generation per year, are full grown in fall, overwinter in the gall in a cocoon, and pupate the following spring. Infested twigs are considerably stunted.