Perdita Cockerelli, n. sp.—♂. Head and thorax green, finely roughened, metathorax sometimes more bluish; face up to antennæ, including labrum and mandibles, except tips, lateral face-marks running to a point about half way between point of insertion on antennæ and summit of eyes, narrow inferior orbits half way up, scape in front, large spot on turbecles, connected with a spot on prothorax and also with coxal cavity, spot on tegulæ, all of legs except black stripe on rear of anterior and intermediate femora and tibiæ and basal half of all coxæ, yellow; black stripes on front and rear of hind femora connected below, hind tibiæ black, with a yellow stripe in front, flagellum reddish testaceous below; wings milky hyaline, nervures pallid, costa, radius more or less and margin of stigma brownish; tegulæ pallid; pubesecence of head and thorax long, white, abundant on pleura and cheeks, tarsi yellowish testaceous, hind tarsi dark; abdomen brownish black, segments 1–5 with yellow bands narrowly interrupted medially; that on 5 sometimes reduced to two spots; venter yellow, tip dark.