HYMENOPTERA. 647 



D. Vein V 3 arising at or beyond the end of the 2d cell III (Fig. 



773)-* 



E. Petiole of abdomen cylindrical, smooth ; antennae slender 



at apex ; tibiae of middle legs with two apical spurs, p. 650. 



SPHECIDjE. 



EE. Petiole of abdomen depressed and generally furrowed 

 above ; antennae thickened at apex; middle tibiae with one 



apical spur. p. 655 MIMESID^E. 



DD. Vein V 3 arising before the end of the ad cell III. 



MELLINlD^E.f 



CC. Base of abdomen without a long, slender portion (not 

 pejtiolate). 



D. Veins Va and V 3 arising from the second submarginal cell 

 (III 5 ) (Fig. 775); sometimes vein V 2 arises from the end of 

 cell III.. 



E. Fore wings with an appendiculate cell (Fig. 775, ap^\ 

 mandibles usually more or less deeply notched on the ex- 

 terior margin, p. 652 LARRID^E. 



EE. Appendiculate cell wanting; mandibles with the ex- 

 terior margin entire. 

 F. Labrum short, projecting but little, if at all. p. 654. 



NYSSONID^:. 

 FF. Labrum distinctly exserted, sometimes forming a long 



triangular beak (Figs. 776, 777) 652 BEMBECID^E. 



DD. Vein V a arising from cell III 4 and vein V 3 from cell Ills 



(Fig. 779). p. 654 PHILANTHID.. 



BB. Fore wings with two closed submarginal cells (Fig. 781, 2d 

 III + III 6 and III 4 ). 



C. Prothorax long and narrow, produced anteriorly into a neck. 

 (As this family includes only a single American species, and 

 that a very rare one, it is not discussed in this work.) 



AMPULICIDiE. 



CC. Prothorax short, transverse, p. 655 PEMPHREI^ONID^E. 



BBB. Fore wings with only one closed submarginal cell (Fig. 783, 

 2d III + III 5 ). p. 656 CRABRONID^E. 



* Vein V 3 is the vein between celts V and ist V 2 , and between cells V 3 

 and ist V 2 . In the species represented in Figure 773 it arises nearthe middle 

 of cell III 6 and extends backward for more than half its length. 



f This family includes only two species found in the Rocky Mountain 

 region, and a single, very rare, one found in the Eastern States, It is not 

 discussed in this work. 



