1^64.] 19 



punctured. Wings subhyaline, apical niargins clouded ; nervures black. 

 Legs black, with black hairs ; tarsi beneath clothed with fuscous pu- 

 bescence. Abdomen subglobose, black, with a very slight bluish reflec- 

 tion, polished, minutely punctured ; the pubescence colored above and 

 beneath as in the preceding species. Length Ti lines. 



Hab. — Rocky Mountains, Colorado Territory. One specimen. Coll. 

 Entom. Soc. Philadelphia. 



Closely resembles the preceding species, but differs by the stronger 

 punctation of the head and thorax, by the less robust form and by the 

 different color of the wings. The head in this species is rather larger 

 than the thorax, whereas in huccphala the head and thorax are about 

 equal in size. 



3. 0. longula, n. sp. 



Female. — Head subtransverse, black slightly tinged with deep blue 

 in certain lights, subopaque, very densely, closely, and uniformly punc- 

 tured ; face and clypeus with a sparse black pubescence, that on the 

 vertex ochraceous, and on the cheeks beneath long and fuscous ; cly- 

 peus slightly prominent, with the apical margin subemarginate ; man- 

 dibles rather deeply channelled near the outer margin, apex armed with 

 three teeth, the two innermost ones short and blunt, the outer tooth 

 longer and subacute ; antennae longer than the head, black. Thorax 

 black, with a greenish reflection posteriorly, subopaque, very densely, 

 finely and closely punctured, clothed above with long ochraceous pu- 

 bescence ; tegulae piceous, minutely punctured. Wings subhyaline ; 

 nervures fuscous. Legs black, with black pubescence, tarsi with fus- 

 cous pubescence. Abdomen subglobose, broader posteriorly, black with 

 a greenish-blue reflection, polished, finely punctured ; basal segment 

 above clothed with ochraceous pubescence, remaining segments with 

 short black pubescence; beneath the ventral scopa is dense and black. 

 Length 7 lines. 



Hah. — Rocky Mountains, Colorado Territory. One specimen. Coll. 

 Entom. Soc. Philadelphia. 



4. 0. juxta, n. sp. 



Female. — Head subtransverse, as wide as the thorax, black, with a 

 deep blue reflection, densely and rather strongly punctured, face and 

 vertex clothed with fuscous pubescence intermixed with ochraceous 

 about the base of the antennas and on the vertex ; apical margin of the 



