480 



THE STUDY OF INSECTS. 



family. The first of these is into two groups of subfamilies, 

 and is based upon the size of the alulets. The division is 

 not a satisfactory one ; and it is only given here because it 

 is commonly employed by writers on the Diptera, and a 

 more definite one has not yet been discovered. 



A. The alulets large; face with a depression or vertical grooves 

 beneath the antennas; cell Ills closed or narrowly open, except in 

 the Anthomyiinae, where it is widely open. p. 480. 



Calyptrate Muscid.<e. 



AA. The alulets small or wanting; form of face varied; cell III* 

 usually widely open. p. 484 Acalyptrate MusciDjE. 



I. Calyptrate Muscid^e (Ca-lyp'trate). 



To this division belong our most familiar representatives 

 or the family, of which the House-fly and the flesh-flies are 

 good illustrations. As a rule cell III 5 of the wings is closed 

 or narrowly open (Fig. 588) ; but in the last subfamily this 



v } + VII, 



Fig. 588.— Wing of Musca domestica. 



cell is widely open (Fig. 589). Five subfamilies are classed 

 here ; these can be separated by the following table, which 

 is based on one given by Professor Williston. 



A. Cell III S of the wings closed or more or less narrowed at the 

 margin of the wing (Fig. 588). 



B. Antennal bristle wholly bare. p. 481 Tachinin/E. 



HB. Antennal bristle distinctly pubescent or plumose. 



