ENTOMOLOGY 869 
Enderlein for the African species, viz., Mesomyia and Dasycompsa, seem to 
correspond to fairly natural divisions and comprise species that are undoubt- 
edly not congeneric with Silvius vituli (Fabricius). 
For the present, however, I cannot separate Silvius from Perisilvius. Ac- 
cording to Enderlein, Perisilvius differs in lacking the appendix at the fork of 
the third longitudinal vein and in the short palpi, which are only one-third the 
length of the proboscis and end in a slender oval segment. The presence or 
absence of an appendix in the wing is a variable character and, in my opinion, 
not of generic value in this group. Of two females of Silvius vituli before me, 
one has a long appendix in each wing, while the other lacks even a trace of it 
in both wings. The different size of the palpi appears to be a common second- 
ary sexual character in this group: they are often considerably smaller in the 
male, and the only specimen of Perisilvius seen by Enderlein was precisely 
of that sex. Szilidy (1926, Zool. Anzeiger, LX VI, p. 327) also reached the 
conclusion that Perisilvius is not generically distinct from Silvius. 
If the eyes of Perisilvius nyassicus Enderlein are actually bare in the male, 
as would appear from Enderlein’s generic key, that species is probably a true 
Silvius. The following are also possibly members of this genus: Stlvius cal- 
losus Ricardo (1920, Ann. South Afr. Mus., XVII, p. 529; 9), of Natal, 
described as having bare eyes in the male and a lineal frontal callus in the 
female; Stlvius cuneatus Loew (1858, Ofvers. Vet. Ak. Forhandl., XIV (1857), 
p. 388; ?), of the Cape Colony, placed by Loew among the species with 
bare eyes and without projecting upper edge to the third antennal segment; 
it is described as having a lineal frontal callus in the female and is possibly 
the same as S. callosus Ricardo; and Silvius confluens Loew (1858, Ofvers. Vet. 
Ak. Foérhandl., XIV (1857), p. 338; ~), of the Cape Colony, similar to the 
foregoing, the fusion of the discal and third posterior cells of Loew’s type being 
probably accidental. Neither of Loew’s species has been studied in recent 
years or recognized again in South Africa. 
Mesomyia Macquart 
Mesomyia Macquart, 1850, ‘Dipt. Exot.,’ Suppl. IV, p. 37. Monotypie for Mesomyia decora 
Macquart, 1850. Enderlein, 1925, Mitt. Zool. Mus. Berlin, XI, 2, p. 312. 
Dasysilvius Enderlein, 1922, Mitt. Zool. Mus. Berlin, X, 2, p. 348. Monotypie for Pangonia 
variegata Fabricius, 1805. 
The above synonymy is after Enderlein (1925), since Pangonia variegata 
Fabricius is unknown to me. 
Of the Ethiopian species formerly placed in Silvius, the following seem to 
belong to Mesomyia: M. decora Macquart ( = Silvius decipiens Loew), M. fal- 
lax (Austen) ( = Silvius schoutedeni J. Bequaert), M. costata (Loew), M. hir- 
suta (Ricardo), and M. monticola (Neave). All these species have hairy eyes 
and the third segment of the antenna more or less crescent-shaped. The generic 
position of Hrodiorhynchus pusillus Schiner is doubtful, although the densely 
hairy eyes most likely place it near Mesomyza. 
I have before me two males from Willowmore, Cape Colony (H. Brauns), 
