The True Flies 



monest forms are neglected by students. One not only does not 

 find them in collections, but when an attempt is made to find what 

 is known about their lives it often results that no information can 

 be gained from books. The reason for this in part is that every- 

 one thinks that everything must be known about these common 

 things. 



The classification of the Diptera is complicated. The order 

 has been split up into many families and the determination of 

 species and genera in many of these families is exceptionally dif- 

 ficult. For the following table of the families and higher groups 

 the writer is indebted to Mr. D. W. Coquillett, and it is taken in 

 part from the advance sheets of a paper about to be published by 

 the U. S. National Museum. 



TABLE OF THE HIGHER GROUPS 



Antennae conspicuous, inserted at upper end of the face, some- 

 times many-jointed, proboscis usually furnished with terminal 

 lips, body rather soft and brittle, legs approximated, wings 

 usually present and frequently furnished with a discal cell ; 

 adults oviparous or larviparous, never in all their stages, liv- 

 ing externally on mammals, birds nor honev bees (Suborder 

 PROBOSCIDEA) '. i 



Antennae usually inconspicuous, commonly inserted near the 

 middle of the sides of the face, and composed of from one to 

 three joints, the apex furnished with a style or bearing several 

 long bristly hairs, proboscis never furnished with terminal 

 lips, body integument tough and leathery, legs on one side 

 of the body usually widely separated from those on the other 

 side, wings, when present, never furnished with a discal 

 cell ; adults pupiparous, living externally upon mammals, 

 birds or honey bees (Suborder EPROBOSCIDEA) 61 



Suborder PROBOSCIDEA Latr. 



I Discal cell, when present, usually furnished with three veins 

 that extend to the wing-margin; frequently four or five 

 posterior cells are present, the third vein sometimes forked ; 

 if the second basal and discal cells are confluent the color 



83 



