74 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[244 



EXPLANATION OF PLATE 



Caudal Aspect of the Head 



Bibio fcmoratus, male. 



Bibio fcmoratus, female. 



Limnobia immatura. 



Sphyracephala brevicornis. 



Tipula bicomis. 



Psorophora ciliata, female. 



Empis clausa, female. 



Exoprosopa fasciata. 



Mydas clavatus. 



Psilocephala haemorrhoidalis, female. 



Ochthera mantis. 



Lonchoptera lutea, female. 



Leptis vertebrata, male. 



Stratiomyia apicula, male. 



Oncodes costatus. 



Pipunculus cingulatus, female. 



Scenopitius fenestralis. 



Dolicliopus sp. 



Oncodes costatus. ventral aspect. 



Platypcza velutina. 



Aphiochacta agarici. 



Dolicliopus bifractus, lateral margins incomplete. 



