A SHORT ACCOUNT OF THE MORE IMPORTANT CHAR- 

 ACTERISTICS OF THE FAMILIES OF DIPTERA. 



Family Pulicidce. 

 Parasitic insects, with scale-like rudimentary wings ; long legs, 

 very large coxse, tibise spurred. Eyes may or may not be present. 

 Thorax composed of three distinct segments. 



Family Cecidoinyida:. 



Ocelli often absent. Thorax with no transverse suture. Antennae 

 moniliform, 24-jointed in (^, 12 to 14 in the ?. Wings with only 

 few nervures. Coxce not elongated, femora not thickened, no spurs 

 on tibiae. 



Family ATyceiophilid(z. 



Ocelli two or three ; often so small they can only just be discern- 

 ible. Thorax with transverse suture. Antennae usually i6-jointed. 

 Eyes generally round. Few nervures in wings, no discal cell. 

 Tibije spurred, coxee elongate. 



Family Bibionidce. 

 Ocelli three. Thorax without transverse suture, pro-thorax largely 

 developed. Eyes of $ large and contiguous, small in ? . Antennae 

 9-jointed. No discal cell in wings. Feet armed with long em- 

 podium, pulvilli present in some genera. 



Family Simulidce. 

 Ocelli none. Thorax without transverse suture. Posterior tibise 

 and first joint of hind tarsi dilated. Antenna cylindrical, 11 -jointed. 



Family Chironomidce. 

 Head small, retracted ; often partly covered by thorax. Ocelli 

 none. No transverse suture on thorax. Eyes reniform. Antennce 

 from 6 to 15 joints; pectinate in $, simple and composed of fewer 

 joints in ? . Wings without vein along the posterior margin ; costal 

 vein ending near the tip of the wing. 



