March, 1896.] FoX, NORTH AMERICAN SPECIES OF NySSOX. 
15 
15. Nysson rufiventris Cress. 
Nysson rufiventris Cresson, ibid, p. 283, 9 • 
Montana; Colorado. 
16. Nysson fidelis Cress. 
Nysson fidelis Cresson, ibid, p. 282, 9 g . 
Montana; Colorado. 
17. Nysson simplicicornis, sp. nov. 
g —Cheeks not margined posteriorly beneath, rather finely punctured; front 
with distinct, somewhat separated and strong, punctures, slightly prominent above the 
antennae; between ocelli flat, not tuberculate; clypeus transversely depressed before 
apical margin, which is subtruncate ; antennae slenderer than in the allied species 
scape shining, punctured, flagellum opaque, the apical joint not curved or enlarged, 
obtuse at tip, the preceding joint not at all produced at apex beneath ; dorsulum with 
coarse shallow punctures, or rugoso-punctate; scutellum coarsely punctured, not 
margined laterally; mesopleurse coarsely punctured but less so than the dorsulum ; 
middle segment with the spines sharp, slender, enclosure irregularly ridged; hind 
tibiae not spinose; wings sub-hyaline, nervures and stigma black, petiole of second 
submarginal cell shorter than the height of cell, submedian cell of posterior wings 
terminating at the origin of the cubital vein, punctures of the abdomen distinct, finer 
and closer, however, than in lateralis , second ventral segment strongly convex, with 
the punctures sparser, last dorsal bidentate. Black ; spot at apex of four anterior 
femora beneath and on dorsal segments 1-3, whitish; mandibles reddish medially; 
tarsi somewhat testaceous; clypeus and sides of face with dense silvery pubescence. 
Length 5 mm. 
Ingham County, Michigan (G. C. Davis), July 17th. Smaller 
than the allied species with black abdomens and is at once separated 
by the different terminal antennal joint. 
18. Nysson opulentus Gerst. 
Nysson opulentus Gerstacker, Abh. Naturh. Gesell. zu Halle, X, p. 114, g 
Nysson opulentus Cresson, Tr. Am. Ent. Soc. IX, p. 279, 9 - 
Nysson opulentus Handlirsch, 1 . c. p. 357, 9 $ • 
New York. The $ I have not seen. 
19. Nysson mellipes Cress. 
Nysson mellipes Cresson, Am. Ent. Soc. IX, p. 279, g 9. 
Colorado; Dakota; Montana. 
20. Nysson tuberculatus Hdl. 
Nysson tuberculatus Handlirsch, 1 . c. p. 363, g 9 • 
Wisconsin and South Carolina (Handlirsch). Unknown to me. 
It is said to be close to basilaris , but seems to differ somewhat in the 
punctuation of abdomen, greater extent of black on legs and presence 
