OF THE TABANID^ OF THE UNITED STATES. 449 



narrowed anteriorly ; callosity black, nearly square, with a short linear, sometimes spindle- 

 shaped prolongation above. Antenna? brownish red, annulate portion black ; upper angle 

 of third joint well marked. Thorax grajdsh black, with white lines ; in well preserved 

 specimens these lines, as well as the sides of the scutellum, are beset with a short, yellowish 

 pubescence ; the scutellum is often, but not always, reddish at the tip, which appears only 

 in denuded specimens ; humeral callosity reddish ; pleura? whitish gray. Abdomen brown- 

 ish black, with a longitudinal, very well marked, whitish or yellowish strijie along the mid- 

 dle, ending at the hind margin of the sixth segment ; this stripe is formed by a grayish 

 pollen as gromid color, whicli is beset with a yellowish pubescence ; two lateral stripes of 

 the same color, subconvergent at both ends, are formed by a series of oblique spots on the 

 segments. Venter whitish, being clothed with a dense whitish j^ollen and a whitish pubes- 

 cence (in some well-preserved specimens the venter is reddish yellow, beset with yellowish 

 hairs ; last segment black, beset with black hair) ; a dark, ill-defined, longitudinal stripe is 

 sometimes visible. Legs : femora dark, paler towards the tip (in some cases pale yellow, 

 except at base), beset with gray pollen and white hairs ; tibioe pale yellow, the front pair 

 black on its latter half; front tarsi black, the four posterior ones brown, yellowish at base. 

 Wings hyaline, stigma pale brownish ; costal cell nearly hyaline ; first posterior cell some 

 times broadly open, in other cases gently attenuated. 



Male. Head not very different in size and outlines from that of the female ; line of 

 division between the large and small facets distinct ; thoracic and abdominal stripes less 

 well marked. Length, 12-14 mm. 



Hab. North America, including Mexico ; this is one of the most common species in the 

 United States ; occurs abundantly in the States along the Atlantic Coast, also in Florida, 

 Texas, Iowa, etc. 



The shape of the front, attenuated anteriorly, the hyaline costal cell and the sometimes 

 reddish scutellum, will help to recognize this species in all its varieties. It varies both iii 

 size and coloring ; the dorsal stripe has sometimes perfectly even edges, sometimes it is 

 jagged, being expanded at every incisure ; the same is the case with the lateral stripes. I 

 have already alluded to the striking differences in the coloring of the venter. The eyes of 

 the female are banded, the upper band being interrupted before reaching the outer margin 

 of the eye. 



The identification of Fabricius's short description is rendered certain by Coquebert's fig- 

 ures, which he quotes in the Systema Antliatorum. 



The mention of the enil of the scutellum being reddish in Walker's description of T. scu- 

 tellaris, renders its synonymy with Uneola very probable ; I do not understand, however, 

 the description of the gray abdominal middle stripe, " which ceases on the tawny hind bor- 

 ders of each segment." 



The synonomy of T. shnulans I look upon as certain. 



24. Tabanus nigrovittatus. 



Tahanus nigrovittatus Macquni-t, Dipt. Exot., 2" Suppl., p. 24, 111. 



Feviale. Face whitish, palpi pale yellowish white, with some minute, scattered, black 

 hairs ; front parallel, yellowish-gray ; frontal callosity dark brown or black, a short, sjiindle- 

 shaped blackish line above it, and usually disconnected from it ; antennas reddish, annulate 



MEMOIRS BOST. SOO. KAT. HIST. VOL. H. 113 



