214 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



hairs form the color pattern, which is fre- 

 quently essential for adult diagnosis. 



No caddis fly genus has been subject to 

 more conjecture regarding the differentia- 

 tion and limits of its species than has Lep- 

 iocella. In the past, some 14 species have 

 been described from America north of Mex- 

 ico. Most of these have been synonymized 

 by Milne (1934, p. 13), who reduced the 

 genus to two species with one species sub- 

 divided into 10 forms. 



Early in our work on the Illinois caddis 

 flies, we discovered that several species be- 

 longing to Leptocella occurred in Illinois 



with conspicuous and constant differences 

 in the larval forms. We have not as yet 

 succeeded in rearing all of them but have 

 reared three in controversial groups. This 

 rearing led to a more detailed study of 

 the adults in our search for specific char- 

 acters and resulted in the discovery that size 

 of eyes and certain differences in male geni- 

 talia could be used to supplement color 

 pattern in the definite diagnosis of at least 

 some species. Most of these adult characters 

 are presented in the descriptions which fol- 

 low. 



I wish to emphasize that there are many 



Fig. 744.— L. albida. 

 Fig. 746. — L. exquisita. 



747 



Larvae of Leptocella 



Fig. 745. — L. diarina. 

 Fig. 747.— Z. pavida. Fig. 748.— Z. Candida. 



