HORSEFLIES OF THE SUBFAMILY TABANINAB 37 
Sziladynus Enderlein, Zool. Anz. 62: 181, 1925. (Genotype, Tabanus aterrimus 
Meigen. ) 
Poecilochlamys Lutz, Estudios de zoologia y parasitologia venezolanos, p. 57, 
1928. (Genotype, Tabanus quadripunctatus Fabricius.) 
Taeniotabanus Krober, Diptera of Patagonia and South Chile, pt. 5, p. 140, 1930 
(nomen nudum); Zool. Anz. 94: 69, 1981; Rev. Ent. 2: 201, 1982. (Geno- 
type, Tabanus occidentalis Linnaeus.) 
Therioplectes authors (not Zeller). 
Generic characters.—Kye bare or pilose; vertex smooth or with an ocellar 
tubercle, but no true ocelli; basal callus well developed, nearly or quite as wide 
as frons; frons never narrowed above; subeallus rarely greatly swollen, and if 
so, the eye hairy; antenna usuaily with a well developed dorsal angle but 
usually without a strong forward-projecting process; if process is present the 
eye is bare; stump vein from vein Ri usually absent and rarely long; cell R; 
usually open and never with a long petiole from wing margin; tibiae not dis- 
tinctly swollen. 
Numerous attempts have been made to divide the genus Tabanus, 
with only partial success. It is obvious that such division would be 
highly desirable, if it could be accomplished, since the genus, as 
commonly recognized, contains species of considerable diversity. 
However, relatively few of the suggested lines of cleavage prove 
satisfactory, and the writer has been unable to find characters that 
will serve to support new divisions. 
In the above synonymy the writer has listed only those proposed 
genera that appear to occur in the fauna under discussion. Meota- 
banus Lutz corresponds to our lineola group and is based on the 
presence of a parallel-sided, middorsal stripe on the abdomen. 
Krober (77) retained it with subgeneric rank, although, as far as 
the writer sees, no structural characters distinguish it, and it con- 
tains species with both bare and pilose eyes. Z'aeniotabanus Krober 
is congeneric with Veotabanus. Poeciloderas Lutz is represented in 
our fauna by 7. reinwardtii and related species. It has been retained 
as a subgenus by Kroéber (7/7) with some justification; certain species 
of the Southwestern States, having pilose eyes but no ocellar tubercle, 
seem to bridge the gap between the true 7abanus and Sziladynus 
(Therioplectes of authors). Dasyommia Enderlein has pilose eyes 
in the male, bare eyes in the female, and a very pronounced ocellar 
tubercle. ‘The writer does not consider its genotype, Tabanus cinctus, 
generically distinct from the many pilose-eyed northern species with 
an ocellar tubercle. The genotype of Dasyphyrta Enderlein is said 
by Krober (77) to be possibly the same as Z'abanus quadripunctatus 
var. amabilis Walker, and, therefore, congeneric with Poeciloderas 
Lutz. Hybopelma Enderlein and Poecilochlamys Lutz have the 
same genotype as has Poeciloderas Lutz. The writer studied the 
type of Hybomitra solox Enderlein and found it to be a typical 
T. rhombicus Osten Sacken. Straba Enderlein is based upon the pres- 
ence of uniformly small facets in the eye of the male, in contradistinc- 
tion to the differentiation found in the male of 7. bovinus. Since this 
character is confined to the male sex and separates species that are 
very similar in all other respects, its value is very doubtful. Szzlady- 
mus Enderlein is congeneric with our pilose-eyed species with a dis- 
tinct ocellar tubercle, such as 7. rhombicus Osten Sacken and 7’. lanif- 
erus McDunnough, the latter more closely resembling the genotype 
than any other of our species. This is the subgenus T’herioplectes of 
authors, not Zeller, the genotype of Zeller’s genus being 7’. tricolor 
