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 eye all small, nearly 
of the same size; abdomen graduallv 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 particular. The front is of 
normal width, the thorax is decidedly vellowish, 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- 
