Iteomyia salicisverruca

Host: Salix humilis and other willows

Salix
Leaf gall
Tube gall, beak on one side of leaf and convex on the other

[A drawing of this gall appears on page 282, Figure 414a]

Galls are monothalamous, 2-3 mm in diameter, and often coalesced. The biology is unknown, but larvae presumably leave the galls in the fall, as do larvae of I salicifolia.

Range: NY, IL, WA, and OR

Cecidomyia verruca

Salix humilis. Mass. Oct. Dome shaped, glabrous, above; turret-like, below. Cells in level of leaf proper.

[Barbour reports finding Iteomyia salicisverruca on Salix hookeriana in a common garden grown in northern California. OTOH, Gagne & Jaschhof's 2021 World Catalog, pg. 378, lists Salix humilis (prairie willow) as the only host, which seems confusing in light of the records the catalog mentions from Oregon and Washington. Barbour's et al.'s drawings, both here and in a paper published in 2020, show hooked red cones, like bird's beaks or rhinoceros horns, protruding from the underside of a leaf.]

Cecidomyia verruca

Cecidomyia salicis-verruca

Monothalamous, subspherical gall on midrib or veins of leaf. Projects very slightly on upper surface, much more on under surface where the insect emerges, apparently, from a neat round hole. (This latter characteristic, so distinct from Walsh's description, has made me mistrust my identification). On two species of willow, Salix. Late summer.

Hormomyia verruca

Subconical, truncate, greenish yellow, lipped gall, diameter 2 mm.

S verruca, n. sp.

On S humilis.

A small, monothalamous, irregularly spherical, greenish yellow gall, .07 — .13 inch in diameter, growing the latter end of August from the midrib or some of the principal veins of the leaf, half of it projecting from each side of the leaf. The upper side is flattish or with a minute point or nipple, the lower side branches out into a ragged, wart-like excrescence, whence the specific name, which later in the season bursts open so as to afford an exit to the insect. When cut into in August, the external wall of a few galls is found to be rather woody, enclosing a central cell, in which lies the larva; but the majority of them-are still solid. From 1 to 12 are found on a single leaf, several of them being often confluent, but with their internal cells, when they have any, separated by a thin partition, and with separate warts to each on the under side of the leaf, which afterwards open separately.

Rather abundant, but local near Rock Island. Described from 38 affected leaves.

S verruca

Oct. 11th I found several of these galls on S. discolor, undistinguishable from those found on the closely allied S. humilis. The larva was orange-color with the usual whitish bowel-like markings, .08 inch long, 2.33 — 3 times as long as wide, depressed, with a large head. Breast-bone black, elongate-semi- oval and rather longer than wide. Two specimens. Thus we have no less than 4 species of Cecidomyidous galls common to the two closely- allied Willows, S. discolor and S. humilis, viz : S. gnaphalioides, S. siliqua, S. batatas and S. verruca.

Trishormomyia verruca

Salix
Leaf galls

Yellowish, red-spotted gall, diameter .1 inch, midge, summer