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Rh TYPES.—8 females, no galls. All the types temporarily in the Kinsey collection. Labelled Bromme, Denmark; gall September 29, 1927; E. B. Hoffmeyer collector.

This insect is known from only two localities in Denmark, but we have additional insects which are intermediate between atrifolii and folii from Strödam, Stiznaes, Moesgaard, and Basnaes in Denmark (all Hoffmeyer coll.). The probable occurrence of atrifolii in a pure population in more northern areas of Europe is indicated by the occurrence of such northern varieties in other species of Cynips in both Europe and America.

AGAMIC FEMALE.—The entire insect rich rufous and piceous (Central Europe) to entirely black (more northern Europe); the head slightly narrower than the more slender thorax (Central Europe) or practically no narrower (more northern Europe); the mesonotum largely punctate and hairy (more Central Europe) or largely naked (more northern Europe); the abdomen not more than half again as long as high, strongly produced dorsally, the tip of the second segment approaching the tip of the abdomen dorsally; the tip of the second abscissa of the radius not bent, usually triangulate but never large; the length 1.9 to 3.8 mm. in two varieties.

The Central European variety longiventris (q.v.) is nearly identical with C. folii folii and close to C. divisa divisa of the same region; the more northern variety forsiusi (q.v.) is very near C. folii atrifolii and C. divisa atridivisa of that region.

BISEXUAL FEMALE AND MALE.—As described for the genus and subgenus (q.v.). Differing from the bisexual forms of other species of European Cynips in having the legs duller yellow with the femora more or less piceous and the mesonotum and mesopleura entirely smooth and shining.

AGAMIC GALL.—Of moderate size, spherical or somewhat ellipsoidal, solid, spongy, but harder than folii. Very regular in shape, only younger specimens becoming distorted in drying; up to 11. mm. in diameter; externally (usually) smooth and naked, occasionally with small, blunt projections on the gall; yellowish-green, then yellow or reddish in color, banded with irregular, concentric, rose-colored, purplish rose, darker brown, or purplish brown bands. The outer shell thicker, harder than in folii, distinguishable from the compact mass of radiating, much branched fibers that fill the gall; this mass not showing the lines of radiating fibers. The larval cell central, oval,