Rhopalomyia californica 

Renamed as R. clinata by Gagne in https://doi.org/10.1093/aesa/68.3.482

Diarthronomyia californica

Cecidomyiidae

Rhopalomyia

Artemisia californica

California

Rhopalomyia clinata

Subconical, thin-walled, obliquely-set, brownish or reddish leaf galls with a length of 1.5 mm, and a diameter of 0.5 mm.

Little known midge galls of certain composites

Diarthronomyia californica Felt 1912:752, Junior secondary homonym of Rhopalomyia californica Felt 1908. 
Rhopalomyia clinata Gagne 1975:483, new name for californica (Felt 1912a)

Lectotype, male, here designated, Claremont, Los Angeles Co., California, C. F. Stahl, emerged III-12-1912, "Artemisia californica"

This is small, brown, monothalamous, subconical, thin walled, naked, and protrudes at an oblique angle from the surface of the leaf. The gall is figured in Felt (1940). 

Biology and taxonomy of the Rhopalomyia Gall Midges (Diptera: Cecidomyiidae) of Artemisia tridentata Nuttall (Compositae) in Idaho

Rhopalomyia clinata
Leaf Gall Midge

The midge induces small, tubular, thin-walled, monothalamous galls on leaflets of California sagebrush.