7 6 NORTH AMERICAN DI1TKRA. 



MYODARIA. 



The very large group of flies, called here the Myodaria, 

 after Desvoidy, -and very commonly known in the past 

 as the Muscidae, sens, lat, has been divided into many 

 lesser groups by students of the order. The number and 

 limitations of these groups are the subjects of most diver- 

 gent opinions, no two writers agreeing. I have, in gen- 

 eral, followed the opinions of Loew and Schiner where 

 I had none of my own, with some suggestions from 

 Czerny and Henclel. In deference to common usage I 

 give the family termination to the names of the groups 

 adopted, not because I believe that they are of equivalent 

 rank to the families, as generally accepted, of the Cyclor- 

 rhapha, for I most emphatically do not, but because of 

 common vogue. It really matters little what they are 

 called, so long as it is distinctly remembered that they 

 have in general less morphological significance. The 

 only danger is that the other families may be broken up 

 into countless groups of equivalent rank, a result to be 

 deplored and which would serve no useful purpose. 



The family, or superfamily, whatever it be, includes 

 more than a half, perhaps, of all living diptera. They, 

 and especially the Calypterae, are the dominant diptera 

 of the present time, the latest and most highly special- 

 ized types of the order. And it is because of this dom- 

 inance that they are exceedingly hard to classify clearly 

 and distinctly. Nor will their classification approach a 

 much more satisfactory equilibrium until more of the 

 world's fauna is known, especially in view of the fact 

 that the smaller forms in particular have been, in gen- 

 eral, largely neglected by competent students as the 

 proletariat of the order. 



