104 SYRPHIDJ2. 



the male; hind borders narrowly pale; male genitalia shining 

 black ; hair at the base of the abdomen pale ; venter black, the 

 sides and hind margins of the ventral plates yellowish. Legs bare, 

 of a reddish-yellow colour; coxae black, but those of the front 

 pair yellowish ; hind trochanters black ; front tarsi broad, black ; 

 middle tarsi dark brown, but the basal joint partly yellow; hind tarsi 



Fig 1 . 17. Chasmomma femoratum, sp. n. $. 

 Left hind leg from inner side, X 10. 



very strong and broad, intensely black ; hind femora broadly black 

 at end, especially in the female, provided with eight to ten bristles ; 

 hind tibiae intensely black, only the knees yellowish. Wings greyish 

 hyaline, the stigma and subcostal cell blackish ; apical half more or 

 less inf uscated. 



Type c? , an additional specimen, and type $ , from Oshogbo, 

 S. Nigeria, xi. and xii. 1910 (Dr. T. F. Gr. Mayer) ; another male 

 specimen from Ibadan, S. Nigeria (Capt. Leslie). 



Genus 21. SYRITTA, Saint Fargeau et Serville (1825). 



This genus seems to be very abundantly represented in tlie 

 Ethiopian Region, more than 20 species being already described ; 

 the species, however, appear to be very closely allied to each other, 

 and as regardi the coloration of the legs as variable as our 

 S. pipiens. Only a few of these species (such as nigrifemorata, 

 latitarsata, and spinigera) are distinguished by good structural 

 characters, the others are possibly not more than colour- varieties. 

 The " species " in the Collection may be separated as follows : 



] (4) Vena spuria not distinct, nearly obsolete, 

 other veins of a yellowish colour; hind 

 femora with a very long and strong 

 &pine near the base ; yellow abdominal 

 bands of male not interrupted in the 

 middle; third antennal joint in great 

 part black ; last ventral plate in the male 

 with a tuft of erect bristly hairs in front 

 of the g'enitaiia. 



