April, 1920] Horseflies From Middle America 191 



pollinose. Abdomen above dark with a gray pollinose posterior margin 

 to each segment slightly widest on the middorsal line; ventrally sim- 

 ilarly colored. Front gray of medium width, frontal callosity shining 

 black, elevated, widest below where it is only slightly narrower than the 

 front, gradually narrowed above and reaching only a little more than 

 half way to the vertex. Antenna reddish brown, somewhat fuscous, 

 first segment somewhat enlarged, third segment with a prominent angle 

 at base above, wide annulate portion elongate, longer than the basal 

 portion. Palpi slender, almost as long as the black proboscis. Wings 

 hyaline, a very short stump near the base of the anterior branch of the 

 third vein, first posterior cell wide open; legs entirely black in all their 

 parts. 



Holotype female from Mallali, British Guiana, April 31, 

 1907. In my collection. 



Tabanus bruesii n. sp. 



Total length 9 millimeters. Body dark grayish fuscous all over. 

 Thorax without stripes but clothed with gray vestiture. Abdomen dor- 

 sally dark with a narrow pale posterior border to each segment, ven- 

 trally similar. Front wide, frontal callosity as wide as the front, wider 

 than high, shining black, rectangular, above with a short connected 

 line which almost but not quite reaches a wide shining black broadly 

 cordate spot at vertex. Antenna nearly black, small, slender, first seg- 

 ment nearly cylindrical, third segment with almost no basal prominence 

 above, annulate portion shorter than the basal portion. Palpi white, 

 robust, very short, nearly the same length as the very short black pro- 

 boscis. Wings hyaline, no stump on the anterior branch of the third 

 vein, first posterior cell wide open. Legs mostly pale, femora with 

 darker streaks, extreme tips of tibiae, especially the front ones, and all 

 the tarsi somewhat darker in coloration. 



Holotype female from San Bartolome, Peru, July, 1913, 

 collected by C. T. Brues. In my collection. 



Tabanus tacitus n. sp. 



Total length 15 millimeters. Thorax dark narrowly striped with 

 reddish brown. Abdomen above red with a narrow black middorsal 

 stripe, lateral margins of the segments narrowly black and furnished 

 with black pile; ventrally the color is similar to the dorsum. Front of 

 medium width, sides parallel, yellowish gray pollinose, frontal callosity 

 dark brown, widest below, scarcely as wide as the front, gradually nar- 

 rowed to a line above reaching to three-fifths of the distance to the 

 vertex. Antenna prominent, first segment reddish, enlarged, produced 

 on the upper anterior border and furnished with short black pile. Third 

 segment black, basally above with a distinct angle which is not pro- 

 duced, annulate portion about equal in length to the basal portion. 

 Palpi rather slender, elongate, nearly as long as the black proboscis. 

 Wings pale reddish hyaline, anterior branch of the third vein with a 



