1942 ] 
Tabanidae from Panama 
9 
eluding T. fuscus Wied. and T. cinerarias Wied., for which 
Lutz proposed the names Chelotabanus and Odontotabanus , 
than they do to T. oculus and T. albocir cuius. For this rea- 
son T. ferrifer and T. importunus Wied., which both have a 
small prescutellar black spot, are excluded from the group 
in the present paper. 
The group may be characterized as follows: Medium to 
large sized flies. Eyes bare, unicolorous or with 2 or 3 
green bands. Frons medium to narrow, 6 to 10 times as 
high as basal width. Frontal callus present, of variable 
shape. Vertexal tubercle absent or weakly developed. Sub- 
callus pollinose. Antennae variable, generally with a well 
marked angle above, rarely with a long tooth. Palpi mod- 
erately inflated. Proboscis but little longer than palpi, the 
labella fleshy. Subepaulet with macrotrichia. Wing vena- 
tion normal, or with the first posterior cell closed or co- 
arctate. Appendix on upper branch of third vein present 
or absent. Wings hyaline, smoky, or with clouds on the 
cross veins. Coloration variable, but the prescutellum and 
disc of scutellum clothed with dense black pubescence which 
is more or less completely encircled by light hairs. Abdo- 
men generally with mid-dorsal triangles, sometimes with 
dorso-lateral spots. In a few species the abdomen is uni- 
colorous. The males of some species have the large facets 
much larger than the small and sharply demarkated from 
them, while in others, the facets are not greatly differen- 
tiated. All described males seem to have a small tubercle 
at the vertex. 
Key to females. 
1. Large stout species, 20 mm. or larger. Legs dark 
brown, the fore tibiae darker, unicolorous. Abdomen 
dark brown, black haired, unicolorous. Frontal 
callus a slender line de-filippU. 
Smaller, more slender species, 18 mm. or less. Fore 
tibiae bicolored, or abdomen with light median tri- 
angles, or frontal callus subquadrangular 2. 
2. Fore tibiae prominently white and white haired on basal 
two-thirds. Frontal callus black. Abdominal tri- 
angles pure white. Frons about 10 times as high as 
wide, narrowest below. First posterior cell narrowly 
open, rarely closed albocirculus. 
