30 OHIO STATE ACADEMY OF SCIENCE. 
Front. The anterior surface of the head between the eyes and 
above the antenne. 
Frontal callosity. A prominence slightly above the antenne, pres- 
ent in the female sex only. It varies in form and coloration. 
Hyaline triangle. The hyaline patch beyond the outer border 
of the cross-band in Chrysops. 
Ocelli. The simple eyes are present in many species and absent 
in others. 
Ocelligerous tubercle. A prominence in some species of the 
genus Tabanus where the simple eyes would naturally occur. 
There are no simple eyes in our species of the genus. 
Palpi. These are the only organs included under mouth parts. 
not considered as belonging to the proboscis. They are prom- 
inent and vary in form and coloration. 
Proboscis. The mouth parts other than the palpi taken collec- 
tively. The labium forms a sheath for the others. 
Pulvili. A pair of pads or cushions located one beneath each 
claw at the distal end of each last tarsal segment. Of the 
three pads seen in this location the two outer are pulvilli and. 
the middle one is the empodium. 
| Stigma. A darker patch in the wing in the region of the union of 
the second vein with the costa. 
Subcallus. The part of the front between the antennz and the 
frontal callosity. It is denuded in some species. In others. 
it is denuded in the female and pollinose in the male. 
Tegulae. Two membranous lobes at the base of the wing. Shown 
in Plate II. 
Wing. Reference to Plate II will give an understanding of the 
parts and regions of the wing. 
FAMILY CHARACTERS. 
The family Tabanidz includes medium sized to large insects: 
commonly called horseflies, gadflies, deerflies, dogflies, earflies. 
and various other names. Usually its niembers are readily recog-. 
nized at sight by their form and general appearance. 
The three jointed antenne with the third joint annulated 
and without a style or arista, the rather large tegula, and the 
well developed pulviliform empodia taken together serve to dis- 
tinguish them from other flies in case of any doubt. 
None of the species are really small; the head is large, larger 
and hemispherical in the male, smaller and somewhat flattened’ 
in the female. 
The antennze are porrect and composed of three segments: 
of which the third is compound, having five or eight annulations, 
when there are eight the basal one is only slightly longer than: 
