Near Monument Creek, Colorado Spirngs, my wife and I recently came across an undetermined species of Artemisia, about three feet high, bearing many Cecidomyiid galls. The flies emerged these galls on April 2, and as the species is new, it is herewith described:

Diplosis Coloradella n. sp.—♂. Length hardly 2 mm. Head black; thorax black, reddish posteriorly mesothorax with rows of black bristles; legs reddish-brown, suffused with dusky; abdomen narrow, reddish passing into yellowish, with long lateral hairs, genitalia darker, terminal joint of forceps stout; wings with a very long fringe; first vein reaching costa about or very slightly below middle of wing; third vein reaching the margin at the apex of the wing, but the apex is subtruncate, rather bulging below, so that the most distal point seems a little below the end of the vein; fifth vein forked beyond its middle, but its distal half reduced to mere shadowy lines; antennæ reddish, 15 (2+13) jointed, joints cylindrical, slightly constricted in the middle, pedicillate with very long hairs, terminal joint subacuminate.