36 [April 



and acute ; antennae short, black. Thorax dark blue tinged with green, 

 densely and finely punctured, clothed with long whitish hairs ; tegulse 

 black, shining. Wings subhyaline. apical margins clouded ; nervures 

 fuscous. Legs black, sparsely clothed with short pale pubescence, the 

 tarsi beneath with fuscous pubescence. Abdomen subovate, gi-eenish- 

 blue, shining, densely and minutely punctured, clothed with whitish 

 pubescence, which is short and dense on the apical segments and long 

 and sparse on the basal segments ; beneath the ventral scopa is dense 

 and white. Length 3 lines. 



Hah. — Pennsylvania. One specimen. Coll. Entom. Soc. Philad. 



Resembles 0. pmif/a, and may possibly be the 9 of that species, 

 although it is smaller. 



30. 0. brevis, n. sp. 



Female. — Head large subquadrate, as wide as the thorax, deep blue, 

 finely and closely punctured, clothed with long black pubescence, 

 which is very dense on the clypeus, and slightly mixed with ochraceous 

 on the vertex ; clypeus prominent, anterior margin truncate ; mandibles 

 robust, deeply channelled along the outer margin, and armed with three 

 teeth, the apical one long and subacute, the others short and blunt ; 

 antennae about as long as the head, black. Thorax deep blue, finely 

 and closely punctured, clothed above with ochraceous and beneath with 

 black pubescence; disk in front with a finely impressed longitudinal 

 line ; tegulaj black, shining. Wings subhyaline, apical margins clouded ; 

 nervures blackish. Legs black, clothed with black pubescence. Abdo- 

 men short, subglobose. deep blue, finely punctured, shining ; basal 

 segment above thinly clothed with ochraceous pubescence ; the remain- 

 ing segments with a very short black pubescence ; beneath, the ventral 

 scopa is dense and black. J^ength 4 lines. 



Hah. — Rocky Mountains, Col. Ter. Coll. Entom. Soc. Philad. 



A short robust species, with the head nearly as large as the thorax. 



31. 0. globosa, n. sjj. 



Female. — Head subtransverse, black, densely, finely and uniformly 

 punctured, sides of the face and the vertex clothed with long ochra- 

 ceous pubescence, that on the clypeus short and black, about the inser- 

 tion of the antennas it is slightly mixed with fuscous; mandibles ro- 

 bust, deeply channelled along the outer margins and armed with three 

 teeth, the innermost one bluntly bifid and the apical one long and 



