123 Clarence E. Mickel 
7. Large, 17-20 mm.; eyes divergent at clypeus; frons narrow; fasciae on 
téreites! \CONTIMUOUS! vtcite mite ecru s Cer et en eee ie pruinosa 
Smaller, 14-16 mm.; eyes very slightly divergent at vertex; frons rela- 
tively wide; fascia on first’ tergite almost always interrupted, 
primaaestate 
8. First transverse cubital vein but slightly bent; development of ocelli 
unusual; yellow on sternites limited to lateral spots on 2-4. .arcuata 
First transverse cubital vein normal; ocellar cicatrices normal ..... 9 
g. Species large, 17-20 mm.; discal marks on mesonotum in form of a U, 
complete: orsbrokenwintoespots +i ae iecie cece art ce eee ee sayt 
Species smaller, under 17 mm.; discal marks on mesonotum consisting 
Ota. Pair of mMarcow. LINES w1ee sot ee eos cee eee primaaestate 
Males 
1. Intermediate femora smooth; not distinctly serrate or dentate; second 
and. sixth sternites, without, processes” ....\/0.%!ass a0 es sen ope pruinosa 
Intermediate femora distinctly serrate or dentate .............ee0e- 2 
2. Second and sixth sternites without processes, plain; sternites 2-4 for 
tve:-most*part*blackint ws cca chiens Betercite oan oes eo Oe ee arcuata 
Second and sixth sternites with more or less well developed processes 3 
3. Process on sixth sternite prominent, its ventral surface flattened and 
bifurcate at apex; spur on the middle tibiae not reaching to or 
beyond ithe middle-pomt ot the ybasitarsis ase com reece sayi 
Process on sixth sternite a transverse ridge not sharply pointed but 
slightly curved on either side the midline; fasciae on tergite inter- 
TAL LEC ohare «hese ee ek case aia! Sota INS TART Rta oke kere ane ee belfragei 
Process of sixth sternite prominent, flattened and bluntly pointed; an 
additional pair of small processes or ridges on this same sternite, 
nubilipennis 
Process on sixth sternite not as above; relatively small, acutely pointed 
or if flattened the sixth sternite lacks the lateral processes or 
PLAS OG 22 ccc pe, Mehl al oA ciate © Sete a a lete laden ete laLeslans tate as tt Teienn teierahane ie Seniesa 4 
4.7 Ultimate: teroite black? 27:..cteleiess = ne vs cise emis aisles Ginter spinolae 
Ultimate tergite maculated; fasciae on tergites greenish-yellow, 
primaaestate 
Bembix arcuata Parker. 
1917. Bembix arcuata Parker, Proc. U. S. Nat. Mus., LII, p. 81 
Males 3: McCook (3), July, 1903 (M. H. Swenk). 
Bembix nubilipennis Cresson. 
1872. Bembex nubilipennis Cresson, Trans. Amer. Ent. Soc., IV, p. 
218. 
1895. Bembex nubilipennis Fox, Proc. Acad. Nat. Sc. Phil., p. 361. 
1917. Bembix nubilipennis Parker, Proc, U. S. Nat. Mus., LII, p. 87. 
440 
