90 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



On some specimens a pair of irregular black basal spots is found on 

 the clypeus which spots are lacking on those on which the yellow 

 maculations are best developed. 



It is difficult to distinguish the most highly colored males of this 

 species from the least well maculated males of sayi. The characters 

 that distinguish this species from the latter are, however, the long 

 apical spur of the middle tibia and the shape of the process on the 

 sixth sternite. The genital stipes of the two are almost identical. 



Habitat. — Yellowstone Park, Utah, Idaho, Wyoming, and Cali- 

 fornia. 



Number of specimens examined — Males, 17; females, 5. 



BEMBIX SAYI Cresson. 



Figs. 150, 151, 190, 211. 



Bembex sayi Cresson, Proc. Ent. Soc. Phila., vol. 4, 1865, p. 467, female. 

 Bembex sayi Handlirsch, Sitz. Acad. Wissensch. Wien, Math.-Nat. CI., vol. 102, 

 1893, p. 877. female. 



Male. — Black: Labrum, mandibles except apices, clypeus, lower 

 part of frons continued upward between the antennae and united 

 with spot in front of anterior ocellus, broad anterior orbits, scape 

 except narrow stripe above, posterior orbits, prothorax entirely, 

 tegulae, lateral lines and a pair of narrow discal lines on scutum, 

 narrow fascia on posterior border of scutellum greatly enlarged lat- 

 erally, narrow fasciae on metanotum, large triangular spot squarely 

 emarginate below on posterior surface of median segment, lateral 

 angles and sides of same, metapleurae, one large irregular spot con- 

 tinued on mesosternum and two small posterior ones on mesopleurae, 

 broad fasciae on tergites 1-6, all undulate laterally and continuous 

 except the first, second inclosing a pair of elliptical dorsal black 

 spots, third, fourth, and fifth biemarginate on anterior dorsal border, 

 second to sixth distinctly notched medially on posterior border, 

 posterior border of first sternite, large lateral spots on second almost 

 united medially, smaller lateral spots on 3-6, legs entirely except 

 black stripe above on anterior femora, small black spots on base of 

 trochanters and at base of posterior femora, yellow or yellowish 

 white. 



The description above is made from the most highly colored male 

 in the series before me. The least highly colored is as follows: 

 Labrum, mandibles except apices, clypeus, lower part of frons, scape 

 below, anterior and posterior orbits, small lateral spots on dorsal 

 border of pronotum, large spot on sides of prothorax including tuber- 

 cles in part, spot on tegulae, minute spot above tegulae on scutum, 

 two spots on mesopleurae, pair of smaller ones on mesosternum, 

 narrow undulate, interrupted fasciae on tergites 1-5, small lateral 

 spots on sternites 2 and 3, spot on anterior and middle coxae below, 



