870 REPORT OF THE HARVARD AFRICAN EXPEDITION 
which I refer to Loew’s Rhinomyza costata (1860, ‘Dipteren-Fauna Siidafrikas,’ 
I, p. 26; «), described from the Cape of Good Hope. The antennae of Loew’s 
type were broken. The species was correctly recognized by Miss Ricardo (1914, 
Ann. South Afr. Mus., X, p. 451; 9°), and should be placed in Mesomyia. 
I have also seen a male of M. decora Macquart (1850, ‘Dipt. Exot.,’ Suppl. 
IV, p. 38, Pl. II, figs. 10 and 10a; ¢), described from Natal. My specimen, 
from Bulawayo, Southern Rhodesia, agrees well with Loew’s description of his 
Silvius decipiens (1858, Ofvers. Vet. Ak. Forhandl., XIV, (1857), p. 338; 2; 
Caffraria), apart from sexual differences. I have followed Surcouf (1912, Bull. 
Mus. Hist. Nat. Paris, XVIII, p. 146) in regarding Loew’s species as identical 
with Macquart’s. The differences between M. decora and M. hirsuta ( = Sil- 
vius hirsutus Ricardo, 1920, Ann. South Afr. Mus., XVII, p. 530; 2a; Cape 
Colony) are very slight and perhaps not of specific value. 
Mesomyia fallax (Austen) 
Silvius fallax Austen, 1912, Bull. Ent. Res., III, p. 113, fig. 1 ( 9%; between Petauke and Har- 
greaves, Luangwa Valley, Northeastern Rhodesia). 
Silvius schoutedeni J. Bequaert, 1913, Rev. Zool. Afric., II, 3, p. 231 (7). New name for Silvius 
fallax Austen. 
The new name S. schoutedent was proposed at a time when both Tabanus 
fallax Maequart (1845) and Szlvius fallax Austen (1912) were still included in 
Silvius. As pointed out by Austen (1913, Ann. Mag. Nat. Hist., (8) XI, p. 562), 
these two species are not congeneric and the change of name was unnecessary. 
Female. — Eyes microscopically hairy. Looking like a small T'abanus, with reddish brown to 
slate-colored head and thorax, and rufous to dark brown abdomen; the tergites with a double 
series of rounded or transverse gray spots connected with the similarly colored hind margins which 
widen into triangles on the middle line. Wings hyaline, with very narrow or indistinct stigma. 
Frons more than twice as long as wide, with a large, quadrate basal callus. Third antennal seg- 
ment with a prominent angle on the upper margin of the expanded base. Length, 10 to 12 mm. 
Male. — Eyes densely hairy. Dorsum of thorax slate black. Abdomen with a broad, black, 
median, longitudinal stripe on the second, third and fourth tergites; the gray spots less conspicu- 
ous than in the female. Length, 9 to 12 mm. 
I have taken one male of this species near Sankisia, in the Katanga District 
of the Belgian Congo. Otherwise M. fallax is known only from Northern Rho- 
desia. 
Dasycompsa Enderlein 
Dasycompsa Enderlein, 1922, Mitt. Zool. Mus. Berlin, X, 2, p. 344; 1925, loc. cit., A, 2 pe elire 
Monotypie for Dasycompsa cincta Enderlein, 1922. 
In addition to the genotype, Dasycompsa comprises also Silvius apiformis 
Neave (1915, Bull. Ent. Res., V, p. 294, figs. 1 and 3; 92), of Nyasaland, 
a female of which is before me. In D. cincta and D. apiformis the structure 
of the third antennal segment is the same! and in general appearance these 
two species are very similar and quite different from Mesomyia. 
1 As corrected in the Errata, Fig. 2a of Neave’s paper (1915) does not represent the antenna of 
Silvius apiformis, but that of Szlviws monticola, in dorsal view. 
