On Freshwater Fossils from Central South Africa. 241 
From an examination of the few specimens in the collec- 
tions I have had access to, Schiner’s remarks appear correct, 
but the drawing of the genitalia of D. cupreus by Loew is 
probably not very correct—it does not represent the genitalia 
of D. chalcogaster accurately. 
Walker’s D. pheax appears to be identical with this 
species, but the type is in very bad condition, from S. Africa 
(Dr. Smith), 44, 6. 
Dysmachus chalcogaster, Wied. 
Zool. Mag. i. pp. 3, 35, 50 [Astlus| (1819); id. Dipt. Exot. p. 189, 13 
[ Astlus] (1821); id. Ausszweifl. Ins. i. p. 442, 26 [Asclus]; Schiner, 
Verh. zool.-bot. Ges. Wien, xvi. p. 684, 26 [Zophonotus]; id. xvii. 
p. 401. 101 [Lophonotus] (1867). 
Dysmachus cupreus, Loew, Dipt. Siidafrik. i. p. 154, 2, pl. ii. fig. 5 
(1860). 
There do not appear to be any specimens of this species 
in the Brit. Mus. Coll., but in the Cape Mus. Coll. are a 
male and two females from Cape Colony answering to the 
description as given by Wiedemann and Schiner. It has a 
golden-yellow moustache, with black bristles at the sides 
and above. Schiner gives the genitalia as long and club- 
shaped, the forceps bifid. The above specimens measure 
23-27 mm.; Wiedemann gives 16 mm. 
[Te be continued.] 
XXXI.—On some Freshwater Fossils from Central South 
Africa. By R. Butten NEwrTov, F.G.S. 
(Published by permission of the Trustees of the British Museum.) 
[Plate VIII. | 
INTRODUCTION. 
THIS communication deals with an enquiry into the history 
of certain obscure freshwater fossils occurring in a highly 
siliceous rock from Africa, the important outcome of which 
is in respect of their geological age. In this connexion, 
therefore, I have had referred to me for determination three 
hand-specimens of a chalcedonized rock containing fossils, 
which have been discovered by Mr. A. J. C. Molyneux, 
F.G.S., in the Matabeleland region of Central South Africa. 
Ann. & Mag. NV. Hist. Ser. 9. Vol. v. 17 
