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 SsOu. apical spurs, p. 650. 



^i^'T Sphecid^. 



EE. Petiole of abdomen depressed and generally furrowed 



above ; antennae thickened at apex; middle tibiae with one 



apical spur. p. 655 Mimesid^. 



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



MELLINIDyE.t 



» 



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

 petiolate). 



D. Veins Va and V3 arising from the second submarginal cell 

 (III5) (Fig. 775); sometimes vein Va arises from the end of 

 cell Ilh. 



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^. 



EE. Appendiculate cell wanting; mandibles with the ex- 

 terior margin entire. 

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



NYSSONIDiE. 



FF. Labrum distinctly exserted, sometimes forming a long 



triangular beak (Figs, ^'jd, jyj) 652 BEMBECiDiE. 



DD. Vein Va arising from cell III4 and vein V3 from cell III5 



(Fig. 779). p. 654 Philanthid.'E. 



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

 III + III5 and III4). 



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 Pemphredonid^e. 



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

 2d III + III5). p. 656 Crabronid^e. 



* Vein Vs is the vein between cells V and ist Va , and between cells V3 

 and ist Va. In the species represented in Figure 773 it arises near the middle 

 of cell Ills 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. 



