

C-Ca^i 



7^ ^ 



Vol. Ill 



ILLINOIS BIOLOGICAL 

 MONOGRAPHS 



October. 1916 



No. 2 



THE HEAD-CAPSULE AND MOUTH 

 PARTS OF DIPTERA 



WTTir TWENTY-FTVn: PI.ATK S 



ALVAH PETERSON 



PRICE $a.oo 



Published by the University of Illinois 

 Under the Auspices of the Graduate School 

 Urbana, Illinois 



