Cynips (Philonix) plumbea
agamic form
GALL. — Spherical, thin-walled, brownish, naked, the centrally- placed larval cell imbedded in spongy or more compact tissue. Monothalamous; up to 11.0 mm., averaging nearer 8.0 mm. in diameter. Strictly spherical except for the broadly flattened base; not at all shrivelled when old; the gall greenish or rose-tinged when young, becoming lead color with a bluish gray bloom that is easily wiped off and largely wears off the older galls, exposing the brownish tan color of the older galls; the surface all but microscopically smooth and naked except for the deciduous bloom. The outer wall of the gall moderately thin but firm because it is inseparable from the rest of the gall; the gall internally more or less compact-crystalline, in some cases indicating a more fibrous structure, the larval cell central, closely embedded and entirely inseparable from the compact material of the gall. Attached by a fine point, singly on the main veins, usually underneath the leaves, on Quercus oblongifolia and Q. arizonica (and related southwestern oaks?). Figures 200, 225-226.
RANGE. — Arizona: Globe (var.? galls, Q. arizonica, Kinsey coll.). Whetstone (galls, Q. arizonica, Kinsey coll.). Oracle (Q. arizonica, Weld and Kinsey coll.). Santa Catalina Mountains (M. Chrisman acc. Weld 1926). Esperara Canyon in Santa Catalina Mountains (types; Q. oblongifolia; Hofer and Edmonston coll.). Sabino Trail in Santa Catalina Mountains ( Q . oblongifolia, Q. arizonica; Kinsey coll.). Santa Rita Mountains ( Q . oblongifolia, Weld and Kinsey coll.). Fort Hua- chuca ( Q . arizonica, Kinsey coll.; gall, acc. Weld 1926). Courtland ( Q . arizonica, Kinsey coll.). Chiricahua Mountains ( Q . arizonica, acc. Weld 1926). Nogales, Patagonia Mountains, and Tumacacori Mountains (galls, acc. Weld 1926). This variety probably restricted to more southern Arizona and southwestern New Mexico, altho related varieties may be expected elsewhere in the Southwest and in Mexico. Figure 36.
The gall of this species is not uncommon in the mountains of southern Arizona, altho we have nowhere seen it as abundant as fulvicollis is in the East. The species occurs on both Q. oblongifolia and Q. arizoniea thruout the forested elevations below six or seven thousand feet, and the insects agree with many other Cynipidae in showing no appreciable variation on these two oaks. The galls of plumbea seem more firmly attached to the leaves than the galls of the easily deciduous fulvicollis. Plumbea galls probably begin development at some time in June. Weld found pupae in some galls on December 7 (1921), but a mature adult in another gall as early as November 24. This adult, when cut from the gall, lived in a pill box until January 1, just as it would have lived for some time as an adult before emerging from the gall. In this delayed emergence plumbea is in accord with the other species of Cynips . As dates of emergence of the adult, Weld records November 22, December 14 and 30, January 8, 12, 13, 24, and 25, and February 3, 4, and 6. I bred insects on January 6, on other dates in the first half of January? and at some date (unrecorded) after January 16 (gall in 1920). By analogy with Cynips fulvicollis of the present subgenus, the bisexual form of plumbea may be expected in a small, seed-like gall occurring in the buds of the oaks early in the spring.
