Gall. —

Ovoid, hypertrophied leaf buds, length 10 to 11 mm., diameter 7 to 8 mm., two or three frequently being confluent, monothalamous, green or somewhat purplish and externally with short, recurved, aborted leaflets covered with a rather thick, gray arachnose pubescence. Apparently the same species was reared from a similar more globose leaf bud gall at once distinguishable by the absence of pubescence.

Cotton-gall midge

Rhopalomyia utahensis

This midge induces oval, monothalamous galls covered with white cotton-like hairs along stems of rubber rabbitbrush.

[lists this species under the same key entry as Rhopalomyia bigeloviaestrobiloides and notes that they may be conspecific; if so R. bigeloviaestrobiloides is the earlier name]