18(M.] 31 



especially the apical one, with very short pale sericeous pubescence ; 

 beneath, the ventral scopa is dense and white. Length 4 lines. 

 Hah. — Connecticut. One specimen. Coll. Mr. E. Norton. 



Allied to the two following species, but is broader, more robust, with 

 the abdomen shorter and only .slightly convex above. It is distin- 

 guished at once from the three preceding species by its ventral scopa 

 being white. 



21. 0. albiventris, n. sp. 



Female. — Head as wide as the thorax, greenish-blue, shining, some- 

 times entirely deep blue ; densely and finely punctured, clothed with 

 long hoary pubescence ; anterior margin of the clypeus truncate, de- 

 pressed and shining ; antennae as long as the head, black. Thorax 

 dark blue green, sometimes entirely deep blue, densely and finely punc- 

 tured, thickly clothed with rather long hoary pubescence ; tegulai black, 

 shining. Wings either hyaline or subhyaline, nervures black. Legs 

 black, shining, clothed especially beneath with hoary pubescence. Ab- 

 domen ovate, dark bluish-green, shining, densely, very finely and con- 

 fluently punctured ; basal segment above thinly clothed with long 

 hoary pubescence, the remaining segments with very short pale pubes- 

 cence, that on the apical segment more dense ; beneath, the ventral 

 scopa is dense and white. Length 4 lines. 



Male. — Resembles the female, except that the face is densely clothed 

 with long hoary pubescence, the antennai nearly as long as the thorax, 

 and the legs and the abdomen above are more pilose. The apical mar- 

 gin of the sixth segment is entire, and that of the apical segment obso- 

 letely notched in the middle. Length 3J lines. 



Hah. — Conn., New York, Penn. 8 9 , o "J, specimens. Coll. P]ntom. 

 Soc. Philad., and Mr. E. Norton. 



Distinguished from the next species by the much finer and closer 

 punctation, especially of the abdomen. 



22. 0. conjuncta, n. sp. 



Female. — Head as wide as the thorax, dark blue-green, densely and 

 rather strongly punctured, shining, with a blackish opaque patch above 

 the antennas which disappears when viewed in certain lights, clothed 

 with rather long pale pubescence, slightly intermixed with pale fuscous 

 on the clypeus, the anterior margin of which is rather strongly emargi- 



