Callirhytis quercus-operator Dalla Torre amd Kieffer, 1910, Das Tierreich, XXIV, p. 582.
Female.—Generally bright brownish, rufous, median groove essentially lacking; several of the wing-veins very faint, the terminal portion of the subcosta almost lacking, areolet closed. Head: bright brownish rufous, darker toward the cheeks and vertex, tips of mandibles piceous; finely shagreened, a broad median elevation on the face; antennse 12-13-jointed, the last division sometimes obscure, uniformly light brownish rufous, glabrous, the first joint obconical, the second ovate, the third elongate and the longest segment. THORAX: bright brownish rufous, irregularly darker in places; glabrous; the mesonotum finely, shallowly shagreened; parapsidal grooves punctate, widely separated, hardly at all convergent at the scutellum, divergent at the pronotum; median groove faint or lacking; anterior parallel lines fine, not very distinct, extending half-way to the scutellum; lateral grooves almost parallel to the parapsides, extending over half the way to the pronotum. Scutellum rather circular, rugose, the two foveæ broad, deep, shining but sparselv rugose, separated by only a fine ridge; pronotum finely punctate-shagreened, the mesopleurae finely shagreened to striate ventrally. Abdomen: rich rufous, brigbter basally, darker apically and dorsally, essentially smooth and shining, very microscopically punctate; the second segment covering two-thirds of the abdomen; the sheaths of the ovipositor pointing almost vertically. Legs: rather uniformly rufous brown; the tarsal claws darker, simple. Wings: clear, the wing-veins, especially on the basal half of the wings, light brown, terminal portion of the subcosta very faint or lacking; areolet closed; cubitus not reaching the basal vein; the radial cell open; the first abscissa of the radius angulate, the angle about 1200, without a projection into the radial cell. Length: 2.2-2.5 mm.
Male.—Similar to the female, but more generally yellowish rufous, the antennæ, light yellowish rufous, 14-jointed, the third joint incised beneath; the abdomen bright yellowish rufous basally, almost black posteriorly, smaller and more slender, the second segment covering most of the abdomen; length, 1.7-2.2 mm.
[Redescribed from Massachusetts material bred in a series of over 600 individuals.]
Galls.—Large, compact masses (Fig. 32) of wool containing seed-like larval cells. The clusters are irregular in shape, often oval, 4X5.5 cm., more or less, in dimensions, the hairs at first crisp, succulent, greenish, white, or rose-tinged, sometimes deep red, becoming yellowish brown with age, finally weathering bluish gray or black and drying into a shrivelled mass. Within the wool, scattered or in small clusters, are the larval cells, hard and rather thick-walled, oval, about 1.5×3 mm. distributed mostly but not entirely toward the center of the gall. On and involving the young terminal stems, new clusters of leaves, and especially the flower clusters of Quercus coccinea, Q. ilicifolia, Q. marylandica, Q. palustris, Q. rubra, Q. velutina, and likely related oaks.
Cotypes.—Cotype females and galls in the Museum of Comparative Zoology.
The gall of this form is a very abundant early-spring gall in scrub-oak country, appearing with the flowers of the oaks about the middle of May and growing rapidly. It should not be gathered for breeding until after the first of June. for it is succulent when first formed and dries and dies unless nearly mature when gathered. The woolly hairs, Bassett has
