32 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 69 



abscissa of med£>lla shorter than the second; nervelhis not angled, 

 shghtlyciu'vod inwardly below; legs rather slender; hind coxae long; 

 inner spur of middle tibia not distinctly longer than half the mid- 

 dle basitarsus; inner spur of hind tibia much longer than the outer 

 and just about half as long as posterior basitarsus, third segment of 

 hind tarsi distinctly longer than the fifth; abdomen rather narrow; 

 first tergite very narrow at base, much longer than broad at 

 apex, and with a deep triangular pit at base which is margined by 

 sharp ridges that unite behind to form a prominent median longitu- 

 dinal keel extending to the apical third of the tergite; on either side 

 of this keel the tergite is rugose; second and following tergites pol- 

 ished. Ferruginous ; head and antennae entirely black ; palpi blackish 

 or dusky except at tips ; thorax, except the propectus which is black, 

 red; wings strongly infumated; anterior and middle legs black, 

 except the anterior tarsi which are yellowish and the middle tarsi 

 which are brownish; posterior coxae and femora red; posterior tro- 

 chanters, tibiae, and tarsi black; abdomen wholly red. 

 Type.— Cat. No. 28680, U.S.N.M. 

 '■ Type locality. — Biscay Bay, Florida. 

 Described from a single male specimen. Undoubtedly additional 

 material will exhibit some variation in the extent of the black markings 

 of the thorax, and the female will probably be found to have darker 

 anterior tarsi than the type. 



3. BASSUS NIGROTROCHANTERICUS (Viereck) 



Microdus 7iigro'rochantericus Viereck, Trans. Kansas Acad. Sci., vol. 19, 1905, 

 p. 275. 



Type. — In the University of Kansas. 



Exceedingly close to imitatus (Cresson) and possibly the same 

 species. Because of the lack of intergrading forms, however, it seems 

 best to hold it distinct for the present. The unique type differs 

 principally from that of imitatus by the characters noted in the 

 kej", but these differences are found to vary more or less in related 

 species which are represented by more material, and may prove inade- 

 quate for the separation of nigrotrochantericus from imitatus. 



Face a little broader than long to the apex of clypeus; head flat 

 behind; eyes attaining the vertex; thorax slender; parapsidal grooves 

 impressed, polished, not foveolate; the middle lobe of mososcutum with 

 . a low polished longitudinal median ridge; furrow in front of scutellum 

 not distinctly pitted; scutellum weakly carinate at apex; propodeum 

 rather evenly rounded from base to apex, with a low polished me- 

 dian longitudinal ridge and a weak irregular carina adjoining this ridge 

 on either side; propleura completely polished; mesopleura polished 

 with a short weakly foveolate longitudinal furrow; metapleura 

 smooth, weakly punctate; inner spur of middle tibia about half as 



