Xystoteras volutellae Phylloteras volutellae, the conical oak gall wasp, is a species of gall wasp (family Cynipidae),[1] tribe Cynipini (oak gall wasps),[2] found in North America.

[5] Each gall contains a single larva and is formed on the underside of host leaves, often in clusters.

The detachable gall is conical in shape and concave at the top.

[6][7] The adult emerges from the gall in early January, but is otherwise undescribed.

[6] Inquiline species found in the galls include Synergus walshii Gillette, 1896 (Cynipidae).