COiNTENTS 



PAGE 



Intmliu-tioM 217-289 



Mi'tho.ls of eollo('tin,ij; 277 



Methods of rearing 278 



Methods of pre!<erv;itioii 278 



Synonymy affecting family names, 279 



Biology and taxonomy 281 



The egg stage 281 



Larval characters 282 



Food of the larva? 28fi 



Characters of the pupa? 286 



Characters of the imagines 287 



l'''ood of the imagines 288 



Acknowledginents 288 



Keys to subfamilies 289 



Larvie 289 



Pupa? 289 



Imagines 290 



Ccraiopogoniiur 290-361 



Larval characters 290 



Pupal characters 291 



Imaginal characters 292 



Keys to genera 293 



Larva? 293 



Pupa? 293 



Imagines 293 



Keys to larva- and jivipu' of North American species of Ccrntopn<ion and 



ForcipomiiUi 294 



Addendum to Cvrnlopojioiiiiiir 360 



Supplementary key to species of IJctcromjiin 360 



Tdni/puia- 361-398 



Larval characters 362 



Pupal characters 363 



Imaginal characters 363 



Koy to genera (imagines) 36i 



Key to larvic 364 



Key to pupa? 365 



Unidentified larva? ' 397 



ChirotiomiiKf 398-534 



Key to genera 400 



Key to larvic 401 



Key to ])up;i? 406 



Pnidenlified larva; and pui)a' 528-534 



Distribution of CMronomidd' in the Illinois Eiver 534 



Summary of Illinois genera and species in comparison with those recorded 



for other states 530 



Nnndier of Illinois species recorded 536 



Nundier of New Jersey si)ccies recorded 537 



Nuiidier of species recorded by Johannsen 537 



Index to genera and species 539 



