82 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[252 



EXPLANATION OF PLATE 

 Lateral Aspect of the Head showing the Tentorium 



Sphyracephala brevicomis. 

 Sarcophaga haemorrhoidalis. 

 Oecothea fenestralis. 

 Scatophaga furcata. 

 Musca domestica. 

 Hydrotaea dentipes. 

 Thelaira leucocona. 

 Archytas analis. 

 Olfersia ardeae. 



Chiroiwiiius ferrugineovilla- 



tus, female. 

 Chironomus ferrugineovitta- 



tus, male. 

 Bibio femoratus, female. 

 Rhyphus punctatus. 

 Psorophora ciliata, female. 

 Psorophora ciliata, male. 



