1903.] NATURAL SCIENX'ES OF PHILADELPHIA. 611 



except that the scape is. slender, punctured and ferruginous; tegulae 

 ferruginous with a yellow spot: pleura black with an oval yellow mark 

 on posterior part; yellow collar, tubercles, scutellum and postscutellum 

 as in modesta; median depression of scutellum ferruginous ; metathorax 

 without 3^ellow spots, its pubescence very short and conspicuously 

 plumose; wings dusky, very dark at apex; stigma ferruginous, nerv- 

 ures rather pale fuscous; second submarginal cell very broad above; 

 third narrow, its outer margin gently curved, greatly narrowed to mar- 

 ginal; basal nervure meeting transverso-medial; legs red; hind femora 

 black behind and beneath except at extreme apex and base ; hind tibise 

 with a large yellow apical spot; hind coxse black with a yellow mark; 

 anterior coxre black with a red apical spot, and long spines ; abdomen 

 black; apical half of first segment fuscous, with an entu-e yellow band, 

 which is indented on each side in front ; second segment with a 

 broad yellow band ; third and fourth with narrow bands, interrupted 

 in the middle, and deeply indented (or interrupted) on each side 

 posteriorly; fifth with a narrow yellow band, and lateral spots; apical 

 plate broad, black, very deeply notched; venter entirely black. 



Hah. — Louisiana, one (No. 2,563) in U. S. National Museum. The 

 third antennal joint is longer than the fourth. The following Cres- 

 sonian species have been examined by Mr. Viercck, and found to 

 have, like A'', crassula, the third jomt longer than the fourth, and the 

 basal nervure meeting transverso-cubital : helfragei, zebrata, ridingsii, 

 modesta, cubensis, krugii, tibialis, limata and scita. The same is true 

 also of N . formida. 



NOMADULA, subg. n. 



Type iV. americana, "Kirby," Robertson, Ckll. l^istinguished by 

 the peculiar male antennsc, the two sexes quite differently colored, 

 the strongly punctured abdomen, and the spined anterior coxse. In- 

 cludes N. americana, N. martinella, N. scita, N. scitiformis, N. erythro- 

 chroa and N. sophiarimi. This is a compact group, quite distinct from 

 Centrias, the type of which is N. crigeronis. N. erythrochroa is much 

 like martinella, but larger, and with the abdomen much more finely 

 punctured, and the eyes more converging below. 



Nomada sphaerogaster, sp. n. 



9 . — Length about 8 mm. ; black and yellow, with the legs largely 

 red; form very broad (like erigeronis), the abdomen spherical seen 

 from above. The general appearance is so like N. crassula that I 

 thought at first it might be the female of that species; but this cannot 

 be, as the anterior coxce are not spined, and the punctures of the abdo- 



