438 Dr. A. S. Packard, Jr's Revision of the 



hind tibiae yellow at base, black beyond, witb a few spines arranged in 

 rows; tarsi brown, fore pair subfuscous, unguinal joint paler. Abdo- 

 men shorter and stouter than in 0. emarginatus, more finely punctured 

 sericeous, with the usual yellow fasciae ; tip submucronate. 



Length, .22 inch. 



9 . Differs in having paler, more fuscous antennae, black legs 

 throughout, and its fore tibiae are slightly fuscous, tarsi becoming fus- 

 cous towards the tip, unguinal joint much paler. Fasciae of abdomen 

 smaller, much farther apart, as this region is broader than in % . Tip 

 broad spatulate, dark, concolorous with the rest of the abdomen, which 

 is smoother than in £ . 



Length, .24 inch. 



New Jersey, (Ent. Soc. Phil.) ; Dublin, N. Y., (Leonard, Coll. Har- 

 ris). Indiana, (Norton). Maine, August, very abundant. 



Differs from 0. emarginatus by the dull tip of the abdomen, its four 

 small, narrow, membranous appendages and narrow undivided spine; 

 in the sculpturing of the propodeum and the darker legs, much darker 

 antennae, and its black mandibles and stouter abdomen, while the teniae 

 are pale instead of reddish testaceous. It is the most common northern 

 species. 



NYSSON, Latr. 

 Nysson, Latr., Xat. Hist., xiii, p. 305. (1804). 



% . Body coarsely punctured, hardly broader than thorax. Head 

 a little less than half as long as broad, not excavated behind; eyes 

 moderately broad ; ocelli placed in a low triangle directly upon the 

 vertex ; epicranium narrowing more than usual towards the clypeus 

 its front margin being a third narrower than the base, sides straight 

 slightly setose. 



Clypeal region half as long as broad, being ovate, larger and nar- 

 rower than usual, convex, the front of the clypeus itself naked, and 

 slightly thickened and turned up on the emarginate edge. Antennae 

 fourteen-jointed, approximate at base, epicranium between with a tu- 

 bercle and slight tuft of long setae ; flagellum short and much thicken- 

 ed towards the tips; 2d joint short and broad, being half as broad as 

 long ; 3d joint distinct, globose, 4th sub-truncate, beneath much hol- 

 lowed and flattened. Palpi long, joints rather slender. 



Thorax sub-globular, convex above; prothorax as broad as the meso- 

 thorax, and much more raised than in Astata and Oocybelus to a level 

 with the head, resembling the Sphecidae in this respect; sides rectan- 

 gular. 



