On the Bombi/llid Fauna of South Africa (Diptera). 37 



but at the Cape there are some striking forms very distinct from the 

 others. Those in the collection can be disting-uished as follows : 



1 (12). Abdomen destitute of black bristles at the hind border of the 



segments at least on the middle line. 



2 (9). Logs mainly yellow, the femora sometimes with dark base. 



3 (f>). Species of very great size (13-16 mm.), without black bristles on the 



abdomen or with yellow ones ; femora almost bare beneath, those of 

 the front pair with many spines underneath. 



4 (5). Proboscis conspicuously scabrose beneath; eyes of male broadly 



separated ; thorax striped on back and pleurae ; pulvilli very small. 



scabrirostris, sp. nov. 



5 (4). Proboscis smooth beneath; eyes of male very approximate ; thorax 



not striped ; pulvilli well developed . . ventricosus, sp. nov. 



6 (3). Species of smaller size, not above 11 mm. in length; abdomen with 



some black bristles ; femora much hairy beneath, those of the front 

 pair not spinose or only with 1-2 spines below. 



7 (8). Scutellum red, at least in the middle; frontal triangle of the male 



small and with a distinct furrow ; mystax yellow ; wings hyaline, 

 with yellow veins ..... simplex, Loew. 



8 (7). Scutellum altogether black ; frontal triangle of the male broad and 



swollen, almost without furrow ; face fringed with rigid black hairs ; 

 wings strongly infuscated, with black veins. tumidifrons, sp. nov. 



9 (2). Legs black, the femora entirely black, or only those of the hind pair 



with pale end. 



10 (11). Species of greater size, measuring not less than 9 mm. in length ; 



scutellum red, at least in the middle ; legs stout and spinose. 



albidus, Loew. 



11 (10). Species of smaller size, not above 7 mm. in length ; scutellum entirely 



black ; legs thin and less spinose . . . nigripes, Loew. 



12 (1). Abdomen with complete rows of very strong and distinct black 



bristles at hind border of the segments. 



13 (14). Eyes of the male separated ; front legs usually black-spotted on 



femora and tibiae ; species of larger size, measuring 7-14 mm., but 

 usxially 10-12 mm. ...... mixtus, Wied. 



14 (13). Eyes of the male almost contiguous; front legs with yellow tibiae 



and femora ; smaller size, not more than 10 mm. in length. 



15 (16). Thorax with yellow hairs, which are rather long, and without bristles 



in front ...... ctenopterus, Mik. 



16 (lo). Thorax clothed with short, paler hairs, which show silvery sheen and 



on the pleura are of a whitish colour, and provided with brownish 

 bristles in front . . spinithorax, sp. nov. 



SYSTOECHUS SCABRIROSTRIS, sp. nov., J 1 , ? 



A gigantic species, very distinct from any other by the pattern of 

 the thorax, by the shape of the labiuai and by the shortness of pulvilli, 

 making a passage to the genus Anastoechus. 



