﻿1927] 



Curran, Diptera of the Belgian Congo 



41 



Tbyridanthrax ternarius Bezzi 



T. ternarius Bezzi, 1924, 'Boml). Ethiopian Reg.,' p. 209. 



The collection contains a female from Faradje, Jan., 1912, which 

 differs from the description only in having the discal cell almost wholly 

 infuscated, although the immediate apex is paler. The legs are mostly 

 missing, only one hind one being intact. 



Thyridanthrax species 

 Four specimens, only one in fair condition, apparently represent an 

 undescribed form but, owing to the fact that it is impossible to determine 

 the color and extent of the pile, it is not deemed advisable to describe the 

 species. So far as I can determine, it is closely related to T. inauratus 

 Klug, from which it differs in having the wing less extensively black, the 

 black pattern being not quite so extensive as in Exoprosopa dimidiata 

 Macquart (see Bezzi, 'Bomb Eth. Reg.,' p. 303) but much the same out- 

 line. The specimens are from the following localities: male, Banana, 

 June, 1915; 3 females, Faradje, Nov., 1912. 



Systropus Wiedemann 

 There are two species in the collection, one of which belongs to the 

 group having the abdominal petiole composed of only two segments, 

 and appears to be undescribed. It differs 

 from related species in having the eyes dis- 

 tincth' separated on the front. 



Systropus snowi Adams 

 S. snowi Adams, 1905, Kans. Univ. Sci. Bull., 

 Ill, p. 156. 



A female from Thysville appears to be- 

 long here, although differing slightly from 

 the description. The wings are wholly 

 brownish and the eyes narrowly separated, 

 the frontal triangle long and slender. In the 

 few species of Systropus known to me there 

 is considerable variation in color and in or- 

 der to properly differentiate the species I 



beheve that the genitalia will have to be studied. In the females these 

 possess excellent characters and the same is also true of the males. 

 The lower genital plate of S. snowi is shown in Fig. 1. 



Fig. 1. Systropus snowi 

 Adams. Lower genital plate 

 of female. 



