54 Journal of Entomolog)' and Zoology 
bles tridentate, the teeth large; clypeus extremely densely punct- 
ured; head with niixeti uhite and black hair, the white conspicuous 
at sides of face, the black especially abundant on lower half of 
clypeus; antenn<e black; thorax above with creamy-white hair, with 
black sparsely intermixed; metathorax with light and dark hair 
mixed; pleura with black hair (no patch of light hair below) ; legs 
black, with mainly black hair; teguls black, with a green spot in 
front; wings dilute brownish; b. n. meeting t. m. ; first r. n. joining 
second s. m. as far from base as length of first t. c. ; abdomen 
shining, the first two segments with glistening white hair, the next 
three with very thin light and dark hair, the sixth appearing green- 
ish (contrasting with the rich purple-blue of the fifth), and hoary 
with appressed white hair; scopa black. 
Habitat: Claremont, California {Baker; Pomona coll. 182, 
part). Resembles O. pikci Ckll., but differs by the much more finely 
punctured clypeus, the much shorter vertex, the much more closely 
punctured abdomen, etc. 
The following key separates the abo\e mentioned species of 
OsDiia; all females with black ventral scopa. 
Hair of thorax abo\e \\'holly or mainly black 1 
Hair of thorax above wholly or mainly light 3 
1. Very small, not quite 7 mm. long cyanosoma sp. n. 
Larger 2 
2. Tibis dark blue cyaiwpoda sp. n. 
Tibia? black pogonigera Ckll. 
3. Small, about 7.5 mm. long nicla)iopIeiira sp. n. 
Larger 4 
4. Hair of thorax above all pale ochreous iinvoinfxiccuni Ckll. 
Hair of thorax abo\e with some dark intermixed 
nigrobarbata sp. n. 
Nomadd crotc'liii nigridf Ckll. 
This was described from the female. The male (Claremont, 
Baker) has no red on the thorax, but there are four small creamy- 
white spots, two at the anterior corners of scutellum, and two on 
postscutellum. Clypeus all cream-colored except upper edge; third 
antennal joint little o\er half length of fourth; legs with more 
