66 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[236 



EXPLANATION OF PLATE 



Cephalic aspect of the Head 



Di.ra clavata. 



Tabanns giganteus, female. 



Tab anus giganteus, male. 



Promachiis vcrtehratus. 



Eristalis tcnax, female. 



Eristalis tcnax, dorsal end of the tormae. 



Eristalis tenax, male. 



Psorophora ciliata, male. 



Strationiyia apicula, male. 



Stratio)nyia apicula, female. 



Exoprosopa fasciata. 



Mydas clavattis. 



Aphiochaeta agarici. 



Platypeca velutina. 



Psiloccphala hacinorrlwidalis, male. 



Leptis vertebrata, female. 



Lcptis vertebrata, male. 



Psiloccphala haeniorrhoidalis, female. 



Lonchoptera lutea, female. 



Pipunculus ciiigulatus, female. 



