25 U. S. NATIONAL MUSEUM BULLETIN 209 



northern limits in the extreme south of the United States. All are 

 large or very large species which provision their nests with mygalo- 

 morph spiders ("tarantulas"). 



Dr. P. D. Hiird has recently published a monograph of the Nearctic 

 species of Pepsis. His keys, synonymy, and distributional conclu- 

 sions are given in a synoptic adapted fashion here for the sake of a 

 complete record of the Nearctic Pepsinae. For more information on 

 taxonomy, biology, and bibliography, or for clarification where the 

 treatment below proves inadequate, consult Kurd's monograph (1952, 

 Bull. Amer. Mus. Nat. Hist., vol. 98, pp. 261-334) or his earlier 

 revision of the Cahfornia species (1948, Univ. California, Publ. Ent., 

 vol. 8, pp. 123-150). 



Keys to the Nearctic species of Pepsis 



MALES 



1. Antenna 12-segmented; subgenital plate in the form of an elongate trapezoid, 



narrowing posteriorly, densely clothed with very long, erect, bristlelike 



hairs, subspecies of Formosa 2 



Antenna 13-segmented; subgenital plate not in the form of an elongate trape- 

 zoid, glabrous or with fine, short pubescence 3 



2. Wings mostly orange la. formosa formosa (Say) 



Wings mostly blackish lb. formosa pattoni Banks 



3. Fourth sternite and sometimes the fifth with dense groups of bristles or hairs 



forming brushes; subgenital plate more or less spatulate, without transverse, 



longitudinal, or toothlike processes on its ventral surface 4 



Fourth and fifth sternites without dense groups of bristles or hairs; subgenital 

 plate various, but always with transverse, longitudinal, or toothlike proc- 

 esses on its ventral surface 9 



4. Bristles on fourth sternite strongly reflexed near their apices 5 



Bristles on fourth sternite not strongly reflexed near their apices .... 7 



5. Antennal sensoria large, basal and apical on the segments, most frequently in 



the form of opposing isosceles triangles or of a constricted band; wings 



entirely blackish 2. saphirus Palisot 



Antennal sensoria small, basal (rarely apical) on the segments, triangular or 

 hemielliptical, impressed, markedly differentiated from the surrounding 

 integument; wings mostly orange 6 



6. Fourth and fifth sternites each with dense bristles or hairs; flagellum with at 



least the apical segment and frequently several or all segments orange. 



3. mildei St&l 

 Fourth sternite with dense bristles or hairs, the fifth sternite with a few scat- 

 tered hairs; flagellum entirely blackish . . 4. angustimarginata Viereck 



7. Fourth sternite with a pair of obliquely arranged rows of backward directed 



bristles, which when seen from below have a semicircular outline anteriorly, 



fifth sternite nearly or quite glabrous, subspecies op elegans ... 8 



Fourth and fifth sternites each with dense, erect bristles or hairs forming 



brushes which in side view are longest anteriorly . . 5. azteca Cameron 



8. Wings mostly orange, rarely blackish; flagellum black, brownish black, or 



rarely orange; range — Kansas and central Texas to Arizona and northern 



Mexico 6a. elegans cerberus Lucas 



Wings entirely black; flagellum orange; range — Carolinian and Austroriparian 

 faunas 6b. elegans elegans Lepeletier 



