August, 1944 



Ross: Caddis Flies of Illinois 



21 



In almost all groups the adults have been 

 separated to species on the basis of genitalia 

 characters. In a few genera, such as Mac- 

 ronemum and Leptocella, genitalia have not 

 given complete diagnosis, and color and pro- 

 portions have been used. 



There is a large amount of information 

 in the literature regarding the immature 

 stages of Trichoptera. Much of this is re- 

 ferred to in various places throughout the 

 text of this report. Additional articles of 

 considerable interest and value are the fol- 

 lowing: Denning (1937), Elkins (1936), 

 Milne & Milne (1938, 1939), Margery 

 Milne (1939) and Ulmer (1902, 1906^). 



illustrated in figs. 20 and 21 which include 

 terms used for larvae, pupae and adults. 



Material Studied 



This report is based on extensive collect- 

 ing over many years, during which a large 

 amount of material has accumulated. We 

 estimate that approximately 750,000 speci- 

 mens were actually collected and checked 

 over. Most of the specimens proved to be 

 females or larvae which could be identified 

 only to genus. About 150,000 specimens 

 have been identified to species, and these 

 constitute the basis for most of this report. 



Terminology 



The terms used commonly in the keys 

 for wing venation and structural parts are 



Disposition of Material 



Unless otherwise noted, Illinois material 

 recorded here is in the collection of the lUi- 



anfenna. 



median ocellus 



anterior wart , 



compound eye --. 



lateral ocellus... 



postero-lateral wart 



pronotum -.. 



tegula..-'"-sc'utum:V.:t 

 mesonotumi scutellum...L, 

 \^postnotum._i!^ 



metanotum / T 



abdomen. 



maxillary palpus 

 labial palpus. 



^emur' jjtjjg/ tarsus'"-^------ 



claws- 



^'^pical spurs 

 ! "^preapical spurs 



Fig. 21. — Rhyacophila lobijera adult male, illustrating terminology ot parts. 



