The Animal Parasites of Man by Fantham, Braun, Stephens, and Theobald
2. Longest hairs in fringe on front margin of
third joint of antennæ, in length equal to
from one-fourth to one-third (not exceeding
one-third) of width of third joint; palpi
of moderate length _tabaniformis_, Westwood.
Longest hairs in fringe on front margin of
third joint of antennæ in length equal to
from one-half to three-fourths of width of
third joint; palpi noticeably long and
slender _nigrofusca_, Newstead.