OF THE TABANID^ OF THE UNITED STATES. 393 



Hah. Cambridge, Mass.; S. Amherst, Mass. (G. Dimmock); Tarrytown, N. Y. ; Dela- 

 ware ; Maryland. Twelve female and two male specimens. 



Two female specimens Avliicli I took at the Trenton Falls, N. Y., in July, 1874, have 

 black frontal tubercles, and the feet more black than usual. I hardly douljt the specific 

 identity of these specimens. 



23. Chiysops obsoletus Wicd. 



CJirysops obsoletus Wietk'niann, Dipt. Exot., i, \k 108, 10 ; Auss. Zweifl., i, p. 211. 



? . Tlie liyaline triangle separating the crossband from the ajiical spot reaches the costa ; both basal cells 

 hyaline ; abdomen bnncu, icilh a ycUoic, ({qxrirnj^ median slripe, ic/iich detes not reach tic tip, and two lettered 

 narroieer, anel still more abbreviated stripes. 



Length, G.5-8 mm. 



Female. Antennoe black ; more or less yellowish at the base ; foce ■\-ellowisli-fevru"'inous 

 facial callosities black ; front yellowish-gray, Avith a large, black callosity. Thorax with the 

 usual greenish-gray median stripe, divided by a black line ; yellowish lateral stripes and yel- 

 loAV stripes on the pleuras. Abdomen more or less dark brown ; a yellow stripe, taperinf 

 posteriorly, reaches from the base of the first segment to the hind margin of the fourth or 

 even the fifth segment ; two lateral, narrower, yellow stripes on the first and a portion of 

 the second, sometimes even on the third and fourth segments, ^^'nter brown, with more 

 or less yellow on the sides of the first tln-ee segments ; a brown lateral stripe often crosses 

 the yellow. Legs reddish, with the end of the front tibia; and the front tarsi, the ends of 

 the four posterior tarsi, the base of the hind femora, etc., black. Wings: two Ijasal, anal, 

 fifth posterior cells and anal angle hyaline ; crossband almost reaching the hind maroin 

 along the vein between the tliird and fourth posterior cells, but leaving a hyaline space on 

 the proximal end of the discal cell and, in the fifth posterior cell, along the intercalary vein. 

 The liyaline triangle between the crossband and the apical spot crosses the second lont)-itudi- 

 nal vein, and touches the costa ; the apical spot is of a paler shade of brown tlian the cross- 

 band and evanescent posteriorly. 



Hab. Pennsylvania; Maryland; Manlius, N. Y. (J. II. Comstock) ; Cambridge, Mass. 

 (Sept. 19); North Conway, N. 11. (August, 1874). Nine females. 



In some specimens the lateral stripes of the abdomen become obsolete ; in others, on the 

 contrary, a trace of a prolongation is visible on the third and fourth segments. Wiedemann 

 mentions a specimen from Pennsylvania, in which tliese stripes almost reached the end of 

 the abdomen. Sometimes the brown tinge of the costal cell is very pjile. 



The male of this species, according to Wiedemann, has no stripes, either on the thorax or 

 on the abdomen. 



24. Chrysops plangens Wiecl. 



Chrijsops plungens Wielenianu, Auss. Zweiti., i, ]i. "210, '22 ( $ ). 



Chrtjsops fuliijinosus Wiedemann, Dipt. E.vot., i, p. 109, 11 ; Auss. Zweifl., i, p. 210, 23 {$). 

 $ . Tiie apical spot is separated from the crossbnid by a hyaline lunule, reaching to tlie costa; first basal 

 cell infuscated ; the brown design on the wing is rather pale ; body altogether grayish. 

 ^ . Altogether blackish; wings j)ale bi'ownish, with some faint paler streaks. 

 Length 5 , 6-8.5 mm. ^ , G.5 mm. 



Female. Head gray; face ferruginous in the middle, with black, shining frontal callosi- 

 ties, separated from the black, shining cheeks by a stripe of yellowish pollen; antennte 



MKMOIRS BOST. SOC. NAT. HIST. VOL II. 



