The True Flies 



10 Tibiae not furnished with apical spurs, ocelli usually wanting, 

 wings mostly with only three veins of which the last 



one is forked ; small, delicate flies ; gall gnats 



Family Cecidomyiidce. 



Tibiae furnished with a pair of spurs at the apex of the inner 

 side, ocelli present Family Mycetophilidce. 



Super-family BIBIONOIDEA Coq. 



II Ocelli absent, or the wings covered with a net-work of 

 creased lines, or the discal cell present 12 



Ocelli present, wings never furnished with a discal cell nor 

 with a net-work of creased lines, the front tibiae are 

 sometimes greatly swollen, or in some cases are fur- 

 nished with a circle of short spines- -Family Bibionidce. 



12 Vertex of head not furnished with ocelli; flies of small size, 13 



Vertex of head furnished with ocelli, wings rather long and 

 narrow 14 



13 Antennae of nearly an equal thickness, wings unusually 

 broad, the veins on the posterior portion faint ; the 

 black-flies Family Simuliidce. 



Antenna very thick at its base, rapidly tapering to a style- 

 like, jointed apical portion, the palpi are almost as long 

 as the antennae; very rare flies- -Family Orphnephilidce . 



14 Wings furnished with a net-work of creased lines, discal 

 cell never present Family Blepharoceridtz. 



Wings never furnished with creased lines, discal cell present; 

 rather large flies Family Rhyphidce. 



Sub-section BRACHYCERA Macq. 



15 Empodium broad, similar to the two pulvilli, third joint of 

 the antennae frequently annulated, body and legs not 

 provided with stout bristles (Super-family Tabanoidea)\6 



Empodium narrow, bristle-like, or wanting, third joint of the 

 antennae never annulated, body and legs frequently fur- 

 nished with stout bristles 21 



Super-family TABANOIDEA Coq. 



1 6 Calypteres very large, or the tibiae not furnished with ter- 

 minal spurs 17 



86 



