The True Flies 



lo — 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 Cecidomyiidcv. 



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

 side, ocelli present Family MycetophilidcB. 



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 Simtiliidce. 



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 Blepharoceridce. 



Wings never furnished with creased lines, discal cell present; 

 rather large flies Family Rhyphidx. 



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. 



16 — Calypteres very large, or the tibiae not furnished with ter- 

 minal spurs 17 



86 



