Dec, 1906.] North American Species of Tabanus. 27 



Tabanus stenocephalus n. sp. General color dark brown, 

 nearly black; head rather small, antenna red with the annulate 

 portion of the third segment black, first segment enlarged and 

 clothed with black hairs above, third segment with a well 

 defined angle above at base, annulate portion shorter than the 

 basal; thorax dark brown above, wings faintly clouded, stigma 

 prominent, brown, longitudinal veins near the apex faintly 

 margined with brown, branch of the third vein without an 

 appendage; anterior leg black except the basal part of the tibia 

 which is white, other legs with basal half of each femur, extreme 

 apex of each tibia and each tarsus black, other parts yellowish ; 

 dorsum of the abdomen very dark brown, a middorsal stripe and 

 an abbreviated lateral stripe on each side clear yellow. 



Female: Length 12-15 mm., front of medium width, narrower 

 than in costalis, yellow pollinose, callosity rather small and 

 shining black. 



Male: Length as in the other sex; head of nearly the same 

 form and size as in the female, facets of the e^'e all small, nearly 

 of the same size ; abdomen gradually narrowed from the base. 

 This sex was taken while hovering in the sun about the middle 

 of the forenoon. 



Habitat: Specimens were taken at Puerto Barrios, Morales, 

 and Panzos, all in Guatemala, during the first half of March. 



In appearance much like appendiculatus, but the head of the 

 male, the dark middle and posterior femora and the simple 

 branch of the third vein are distinctive. Much darker in 

 coloration than costalis. 



Tabanus trilineatus Latreille. Bellardi, in his Diptera of 

 Mexico, included a species which he called trilineatus but Osten 

 Sacken who saw his specimen says that it is a synonym of lineola. 

 The specimens I have placed under trilineatus are mostly from 

 British Guyana, but one or two are from San Carlos, Costa Rica. 

 They are lighter in coloration than specimens of appendiculatus, 

 in fact nearer to costalis in this partictdar. The front is of 

 normal width, the thorax is decidedly yellowish, the wings are 

 hyaline with a rather pale stigma, and the fork of the third vein 

 bears an appendage; the middorsal abdominal stripe is quite 

 wide and the lateral stripes reach the fourth or fifth segment. 

 All these stripes are decidedly yellowish in coloration. The 

 eye of the male has a distinct area of enlarged facets which is 

 separated from the occiput above by a narrow band of small 

 facets. 



Tabanus trivittatus Fabricius. The species I have placed 

 under this name appears to agree well with Wiedemann's descrip- 

 tion of what I suppose were the types that Fabricius described. 

 The most characteristic points in regard to the species are the 

 very narrow front and the very dilute brownish wings. Other- 



