20 [April 



clypeus truncate; mandibles stout, lower margin clianaelled, apex broad 

 and armed with three teeth, the innermost one being short and bifid, 

 and the others long and subacute; antennae short, black. Thorax black, 

 tinged with greenish posteriorly, opaque, very densely and finely punc- 

 tured, clothed above with long ochraceous pubescence, beneath with 

 fuscous pubescence ; tegulae black, finely punctured. Wings subhya- 

 line ; nervures blackish. Legs black, clothed with short fuscous pu- 

 bescence. Abdomen subglobose, finely and rather densely punctured, 

 polished, black with a bright bluish reflection changing to green to- 

 wards the tip ; basal segment thinly clothed above with ochraceous 

 pubescence, remaining segments with a very short scattering black 

 pubescence ; beneath, the ventral scopa is dense and black. Length 

 6 lines. 



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

 Kntom. Soc. Philadelphia. 



Clo.sely allied to 0. longula. but rather smaller, the head longer and 

 broader, the clypeus truncate in front, and the mandibles larger, with 

 their teeth differently shaped, the antennaj shorter, the second subuiar- 

 ginal cell not so broad, and the abdomen not so robust as in that 

 species. 



5. 0. latitarsis. u. sp. 



Male. — Head dark blue-green, densely and finely punctured, clothed 

 with long whitish pubescence which is rather thin on the vertex and 

 cheeks and very dense on the face ; mandibles black, shining, deeply 

 bified at tip, the inner tooth short, broad and truncate, the outer one 

 rather long and acute; antennae black, as long as the head and thorax. 

 Thorax dark blue-green, densely and finely punctured, clothed with long- 

 dense whitish pubescence ; tegulae black, shining. Wings subhyaline. 

 apical margins faintly clouded ; nervures blackish. Legs black, clothed, 

 especially the femora beneath, with rather long whitish pubescence ; tarsi 

 beneath with fuscous pubescence ; the second, third and fourth joints of 

 the intermediate tarsi subtriangular and broadly dilated; the innermost 

 spur of the posterior tibije slightly incurved at tip, very long and about 

 twice the length of the other; basal joint of the posterior tarsi rather 

 long, clavate, broadest at tip ; apical joints of all the tarsi piceous. 

 Abdomen broadest posteriorly, incurved at tip, black, with a blue- 

 green reflection, shining, very densely and finely punctured, apical 



