Callirhytis ellipsoida, new species

Host. — Quercus bicolor Willdenow.

Gall. — Ellipsoid, 4.5 by 5.5 mm., single or in small clusters on the small roots just below surface of ground under the tree. Surface smooth, brown. Monothalamous with a firm wall less than one-half millimeter thick when mature, exit hole at end 2 mm. in diameter. Immature galls lighter in color, fleshy, translucent white inside.

Habitat. — Type locality, Wilmette, Illinois. Collected also at Evanston and Winnetka, Illinois.

Biology. — The galls probably take two years to develop, the larvae transforming to adults the second autumn but not emerging from the galls until the following spring between April 15 and May 7. They are all females. They oviposit at once in the swelling buds of the same tree, but the alternating sexual generation is unknown.

Callirhytis ellipsoida

Quercus bicolor
"Root" galls
Single or in small clusters on the rootlets just below surface of the ground in the fall.

[Photo caption]
On Q bicolor. Galls probably take two years to develop. Larvae transform the second fall and adults emerge the following spring between Apr 15 and May 7 and oviposit in swelling buds on the same tree, all females.