116 GENERA OF IIYMEXOPTERA. 



Anterior wingrs with a distinct sinus between the niaririiial and tliinl sul)- 

 maririiial cells. 



Second siibuiaririiial cell suhtrianjiular, much narroAvcd towards the 

 marginal : labrmn twice as long as broad, not swollen at base; man- 

 dibles slender, unarmed; ma.xilla^. when folded, cimct'aled by the 

 labrum flicrobt'iiibc'x Patton. 



Second submarginal cell subquadrate, not or very slightly narrowed 

 towards the marginal ; labrum not twice as long as broad, swollen 

 at base; mandibles armed with a tooth : maxilhe, when folded, ex- 

 tending beyond the mesothorax Stoiiiulia Say. 



Maxillary palpi long, slender; anterior wings with a distinct sinus between 

 the marginal and third submargiual cells ^loiiofliila Latr. 



To the genus Sphecii(s belong two large species, which have been 

 generally referred to Stizns; one of them, .sperio'<i(.% — an exceedingly 

 variable species found all over the United States — j^reys upon the 

 Cicada, with which it provisions its nest ; an interesting account of 

 the habits of this species is given by Fuller in the " American En- 

 tomologist," vol. iii, p. 167. Megastizvs has one species from the 

 Western States and Texas, and Bemhecinm two from Florida and 

 Texas. To Stizus two species are referred, one of which, IServillei 

 St. Farg., has not yet been identified, while the other, vule'mcfu.^ Say, 

 is very common in the far West and Southwest ; it is black with a 

 broad reddish band on the abdomen, and the wings broad, violaceous- 

 black, with the extreme tij)s subhyaline. 



The Bembecini have not yet been monographed, and considerable 

 confusion exists in the species belonging to the genera Bembex and 

 Monedula, of which seven are referred to the former and nine to the 

 latter, while Microbembex and Steiiin/ia liave each one species. 



Family NYSSONID^. 



Since the publication of Dr. Packard's " Revision nltlie Fossorial 

 Hymenoptera" (Proc. Ent. Soc. Pliil. vi, 1866-67), in which this 

 family was reviewed, nothing has been done in the study of dur 

 species, except those belonging to Ni/s,ioii and allied genera, which 

 have been noticed in a ])ap('r publisli(>d in the ninth volume of these 

 Transactions, 16&2. 



The genera are readily separated by the cliaracters given below. 



Table of Genera. 



Second submargiual cill not petiolatc 2. 



Second submargiual cell petiolate 3. 



