Andricus coronus

Quercus nigra, palustris, phellos
Stem galls, detachable
Terminal cluster in early spring, green, ridged galls pointed at both ends, solid with a central larval cell, dropping when mature.

[Photo caption (no photo)]
On Q palustris, phellos, nigra. A cluster of green, fleshy ribbed thick-walled galls, 8-12 mm long in early spring, dropping when mature in early May (DC). Adults the next spring Apr 25, Apr 26, and Apr 10 in different years.

Andricus coronus sp. nov.

Gall.---Monothalamous. Pale green; soft when fresh, hard and pithy when dry. Rounded, somewhat crown-shaped, with prominent ridges at the side from the base, meeting at the apex; base pointed. Thick walled, with a large round larval cell in the center.

Length 8-12 mm; width 6-12 mm

Habitat.--Bronx Park, NYC, May 18 1905; Atlanta GA; Mississippi

The gall may be found in New York, in clusters on the small terminal twigs of Quercus palustris during the middle of May, and in GA on water oak [Quercus nigra] during March. When mature, they drop to the ground or will readily break off when touched. The imago becomes fully developed in the gall by October, but does not emerge until the following spring.