1893.] NATURAL SCIENCES OF PHILADELPHIA. 541 



6 — Upper surface of metathorax coarsely reticulated, with a central, 

 longitudinal ridge ; stigma of wings yellow ; abdomen black 



apically tricolor. 



Upper surface of metathorax rather finely reticulated, without a 

 central, longitudinal ridge; stigma of wings testaceous, abdo- 

 men not black apically nevadensis. 



7 — More or less red ; tegulee whitish ; wings subhyaline 8 



Ceruleous; wings fuliginous cceruleus. 



8 — Metanotum very finely granulated or coriaceous 9 



Metanotum very finely and transversely striated bellus. 



9 — Wings subhyaline throughout ; mesopleurse sparsely punctured. 



elegans. 



Wings with apical third dark fuscous ; mesopleurse more or less 

 rugose asper. 



1. — Astatus unicolor Say. 

 Astata unicolor Say, Long's Exp. St. Peter's Eiver p. 338 £ • 1823. 

 As/a/ us unicolor Kohl, 1. c. p. 449. 



9 . — Produced portion of anterior margin of clypeus subtruncate; 

 front with tolerably strong close punctures, the vertex with coarse 

 punctures; the punctuation of the region enclosed by the ocelli is 

 much closer than that on front ; ocelli placed in pits, especially the 

 anterior one; antennas tolerably long, the first joint of flagellum one- 

 third or more, longer than the second; clorsulum closely and coarsely 

 punctured, medially the punctures are somewhat sparser; scutellum 

 sparsely punctured medially, slightly impressed; metathorax above 

 very coarsely reticulated, the metapleura? somewhat less strongly so; 

 tibiae and tarsi strongly spinose; with exception of second ventral 

 segment the abdomen is scarcely punctured ; pygidial area about 

 two-and-a- quarter times longer than it is broad at the base. Black; 

 tarsi obscurely testaceous; head, thorax, legs and abdomen beneath, 

 clothed with a long, whitish pubescence which is most dense on the 

 head ; wings with the apical third fuscous, the marginal cell broadly 

 truncate. Length 11-12 mm. 



S . — Produced portion of anterior margin of clypeus subtruncate; 

 front strongly convex, strongly impressed medially and much more 

 closely punctured than in the £ ; joints 3-8 of flagellum rounded- out 

 beneath, the first joint more than one-third longer than the second; 

 dorsulum with the punctures somewhat closer and finer than in 9 ; 

 scutellum but slightly impressed; metapleurse striated, on lower 

 portion punctate; abdomen, ventrally, finely and on the second and 

 third segments sparsely punctured; last dorsal segment coarsely 



