80 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[25ft 



EXPLANATION OF PLATE 

 Lateral Aspect of the Head showing the Tentorium 



Bibioccphala clegantula, female. 



Bibiocephala clegantula, male. 



Rhyphus punctaius. 



Trichocera biinacula. 



Psorophora ciliaia, female. 



Stratiojiiyia apicula, male. 



Mycetobia dirergeits. 



Exoprosopa fasciala, eye removed. 



Dixa clavata. 



Empis clause, female. 



Platypesa velutina. 



Psychoda albipennis. 



Eristalis tcnax, female, eye removed. 



Dolichopus bifractus, eye removed. 



Loxocera pectoralis. 



Rhabdophaga strobiloides. 



Sapromyza vulgaris. 



Drosophila ampelnphila. 



Psilocephala haeinorrhoidalis, female. 



Aphiochacta agarici. 



Euarcsta acqualis. 



Heteroncura flaviscta. 



Lonchoptera lutca. 



Tipuda bicornis. 



Chyromya concolor. 



