ENTOMOLOGY 945 
scutellum; the pollen on the remainder of the dorsum dark brown; longer pilosity white on sternum 
and pleura; the postalar calli fringed behind with long white hairs; short pile black, mixed with 
a few glistening pale hairs on most of the dorsum and scutellum. Abdomen black, moderately 
shiny; dorsally covered with short, brownish black, appressed hairs mixed with a few yellowish 
hairs; extreme base of the first tergite and narrow middle line of the second to fifth tergites with a 
grayish, somewhat glistening pollen; this line widening into narrow triangles at the hind margins 
of the tergites which bear a few silvery or golden-yellow hairs; the small, median, triangular spots 
thus formed are visible on the first to fifth tergites and there is a trace of a similar median spot on 
the sixth; the hind corners of the tergites bear a few white hairs, but they do not form spots and 
are not connected with the median triangles. Ventrally the abdomen is clove brown in the middle 
with short black pile; along each side there is a rather well-defined, broad, grayish brown, longi- 
tudinal stripe, caused mostly by a gray tomentum on a reddish-brown ground color; hind margins 
of the sternites narrowly gray pollinose with a fringe of short, white hairs. Legs: coxae and femora 
black; the coxae with long white hair; the femora with shorter pile, mixed black and gray; 
knees and middle and hind tibiae dark clove brown, the short appressed pile of the tibiae black on 
the outer face, mostly glistening white on the innerface; fore tibiae notswollen, dirty yellow basally, 
dark clove brown apically, the basal two-thirds with many short, appressed, glistening white, and 
a few black hairs, the pile of the apical third black ; under a handlens the base of the fore tibiae 
thus appears dirty yellow like the palpi, but it forms no conspicuous white ring; tarsi dark clove 
brown to black. Fore tarsi not dilated. Wings moderately and fairly uniformly smoky through- 
out, without clearer areas in any of the cells; slightly more brownish toward the anterior margin; 
stigma very elongate, pale brownish; veins dark clove brown; squamae uniformly smoky; halteres 
brown, with the apex of the knob dirty yellow. Fork of third longitudinal vein without appendix. 
ISLAND OF PRINCIPE. — One female holotype, taken while attempting to 
bite man, on the shore of the bay of Sao Antonio, November 26, 1926. 
T’. principis is in general appearance somewhat like 7’. obscurefumatus Sur- 
couf, but it is evidently not related to that species from which it is readily sep- 
arated by the shape of the frontal calli and by the uniformly smoky wings. In 
Surcouf’s classification it could be placed either in his ninth, tenth, or eleventh 
groups, although the total absence of lateral spots on the black dorsal side of the 
abdomen distinguishes it from all the species listed by Surcouf in these groups. 
If the shape of the frons and frontal calli is to be taken as a criterion, 7’. principis 
is perhaps allied to 7. ustus Walker, with which, however, it cannot possibly be 
confused. 
Thaumastocera Grinberg 
Thaumastocera Griinberg, 1906, Zool. Anzeiger, XXX, p. 354. Monotypic for Thaumastocera akwa 
Griinberg, 1906. 
Hybommia Enderlein, 1922, Mitt. Zool. Mus. Berlin, X, 2, p. 348; 1925, loc. cit., XI, 2, p. 340. 
Monotypic for Hybommia nigripennis Enderlein, 1922. 
There can not be the slightest doubt that Hybommia is identical with Thau- 
mastocera. All the generic characters given by Enderlein in 1925 perfectly fit 
the male of 7. akwa. It is true that Enderlein places his new genus in his tribe 
Lepiselagini, characterized by “3. Fithlerglied oben ohne Ecke oder Zahn’; 
while Thaumastocera possesses a long tooth at the base of the third antennal 
segment. The author made, however, a mere guess as to the taxonomic position 
of his insect, since he states in the generic description, as well as in that of the 
type species: ‘‘Fiihler abgebrochen.” 
Thaumastocera is known only from the rain forest of the West African Sub- 
region. It is perhaps the most aberrant of all the Tabaninae, in which subfamily 
it must be placed owing to the absence of spurs on the hind tibiae. The probos- 
