OF THE TABANID^ OF THE UNITED STATES. 445 



margin, expands into a large spot, coalescing with brown clouds at the origin of the fork of 

 the third vein and at the end of the discal cell ; first posterior cell distinctly attenuated. 



3[aJe. Surroundings of the mouth and palpi clothed with blackish hair ; spots on the 

 abdomen replaced by broad whitish crossbands, especially on segments two to four ; in 

 other respects like the female. Length, 14-15 mm. 



Hah. Dallas, Texas (Mr. Boll). A male and a female. Missouri, in July (C. V. Eiley). 



The variegated wings of T. venusius being unique among the North American species, 

 will render it easily recognizable. The head of the male is comparatively small, not larger 

 than that of the female ; the large facets occupy their usual place, but the difference in 

 size Ijetween them and the small ones is so small that it requires a close attention to dis- 

 cover it. 



18. Tabanus psammophilus n. s]i. 



Female. Palpi short and stout, pale yellowish white ; face white, with white hairs ; front 

 gray, remarkably broad, somewhat convergent anteriorly ; callosity black, broader than 

 long, without any linear prolongation aljove ; antennas pale reddish yellow ; third joint 

 tinged with Ijrownish ; its annulate portion black ; in shape the third joint is comparatively 

 narrow, and not excised at all above, so that its upper angle is very little marked. Ground 

 color of the body dark, but almost entirely concealed under a white pubescence. Legs yel- 

 lowish, tips of tiljitx! and tarsi brownish. Wings whitish, with Ijrown veins ; a long stump 

 of a vein near the origin of the upper branch of the third vein; first posterior cell not 

 coarctate. 



Male. Similar to the female, except in the sexual characters. Length rather variable, 

 from 11 to 15 mm. 



Hah. Ft. Capron, Florida, April 10, 1875 (Messrs. Hubbard and Schwarz), on the sea 

 beach ; four males and three females. 



The uniformly whitish coloring of this species, the broad front, the transverse frontal 

 callosity, the long stamp of a vein on the fork, etc., render the species very easily recog- 

 nizable. I suppose that it is imiformly white in life ; most of the specimens before me 

 seem to have somewhat suffered from moisture, and have for this i-eason a darker coloring. 



Li the male the difference between the large and small flicets on the eyes is very marked, 

 the latter occupy a comparatively small space on the underside, and are but little prolonged 

 along the posterior orbit. On the eyes of the female I perceive two approximate, bluish 

 stripes on green ground, the upper and lower portion of the eye being again dark blue (or, 

 in other words, the ground color is blue, with two broad green stripes, the broad interval 

 between which contains a third, much narrower green stripe). 



Tabanus nanus Macquart, Dipt. Exot. Suppl., I, p. 42, from Texas, reminds one of the 

 present species ; but the size given (four lines) is by far too small for identification. At any 

 rate the name nanus cannot be used, being preoccupied by Wiedemann for a species from 

 the Cape. 



19. Tabanus nivosus n. sp. 



Female. Front of moderate breadth, parallel, brownish gray, with brown shadows ; fron- 

 tal callus pale brown, with a stout linear prolongation above ; face white, beset with white 



MEMOIRS BOST. SOC. NAT. HIST. VOL. II. 112 



