Ill 



epipharynx and hypopharynx. Antenna eleven segments. 

 Palpi four segments. 



Simple eyes (ocelli) absent ; thus distinguished from 

 Bibionidae. Eyes in $ joined together (holoptic). The facets 

 on the upper part of the eye are the larger. 



Egg. — Deposited in a compact layer on stones and grass. 

 Egg measures o'40-o'i8 mm. 



Larva. — Twelve segments. On under side of anterior 

 portion is a subconical retractile process crowned with bristles. 

 Anal extremity bristly, with three short retractile tentacles. 



Pupa. — Has a respiratory tuft on each side of thorax. 

 Pupa has spines by which it anchors itself to the cocoon. 

 These can be found under small stones. Pupal stage about 

 five days. 



Genus Simulium. 



Body small, hump-backed, with a hairy felt-work (to- 

 mentum). Head small. Palpi four segments, the fourth com- 

 posed of numerous annuli ; larger in $ than in $ Antennae 

 eleven segments, narrowing to the tip, a little longer than the 

 head. Wings large. First, second, and third veins dark, 

 remainder pale. $ generally black, ^ cinereous. Eyes con- 

 tiguous in $ (holoptic) remote in ? (dichoptic). 



W.no of H aOTUS Sf 



Fig. 90. Wing of Lepidosdaga (Hadrus), a Tabanid. a.c.v. = 

 anterior cross vein ; p.c.v. = posterior cross vein 



The Brachycera (/SpaxiJ? short, Kepag antenna) include the 

 following : — 



1. — Tabanidae (Horse-flies or gad (=sting) flies). 



Large flies. Antenna three-jointed, not terminating in a 

 style or arista (the arista (when bristle-like) or style (when 

 thick) being an appendage of the terminal portion (flagellum) 

 of the antenna). Third segment of- antenna annulated. 



