66 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[236 



EXPLANATION OF PLATE 



Cephalic aspect of the Head 



.ZXi-a clavata. 



Tabanns giganteus, female. 



Tabanus giganteus, male. 



Promachus vcrtebratus. 



Eristalis tenax, female. 



Eristalis tenax, dorsal end of the tormae. 



Eristalis tenax, male. 



Psorophora ciliata, male. 



Stratiomyia apicula, male. 



Stratiomyia apicula, female. 



Exoprosopa fasciata. 



Mydas clavatus. 



Aphiochaeta agarici. 



Platypcza vclutina. 



Psilocephala haemorrhoidalis, male. 



Leptis vcrtebrata, female. 



Leptis vertebrata, male. 



Psilocephala haemorrhoidalis, female. 



Lonchoptcra lutea, female. 



Pipunculus cingulatus, female. 



