HYMENOPTERA. 647 



D. Vein V3 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. 



SPHECID/E. 



EE. Petiole of abdomen depressed and generally furrowed 

 above ; antennae thickened at apex; middle tibiae with one 



apical spur. p. 655 MiMESlDiE. 



DD. Vein V 3 arising before the end of the 2d cell III. 



MELLINIDiE.f 



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

 petiolate). 



D. Veins V 2 and V 3 arising from the second submarginal cell 

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

 cell III,. 



E. Fore wings with an appendiculate cell (Fig. 775, aft.) ; 

 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^e. 

 FF. Labrum distinctly exserted, sometimes forming a long 



triangular beak (Figs. 776, 777) 652 Bembecid^e. 



DD. Vein V 2 arising from cell III 4 and vein V 3 from cell III 5 



(Fig. 779). p. 654 Philanthid.^. 



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

 III + III, and III*). 



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.) 



AmPULICIDjE. 



CC. Prothorax short, transverse, p. 655 Pemphredonid^e. 



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

 2d III + Ills), p. 656 Crabronid^e. 



* Vein V 3 is the vein between cells V and 1st V 2 , and between cells V 3 

 and 1st V 2 . In the species represented in Figure 773 it arises near the middle 

 of cell III 5 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. 



