August, 1944 



Ross: Caddis Flies of Illinois 



49 



2. Basal incision of right mandible very 



deep, fig. 175 socia, p. 51 



Basal incision of right mandible shal- 

 low, fig. 177 3 



3. Marginal lobes of frons slightly farther 



apart, fig. 181; basal incision of 

 right mandible more conspicuous, 



fig. 176 feria, p. 50 



Marginal lobes of frons slightly closer 

 together, fig. 182; basal incision of 

 right mandible less conspicuous, fig. 

 177 aterrima, p. 50 



Adults 



1. Apex of abdomen with a pair of well 



differentiated claspers (males); all 

 characters for couplets 2-5 are illus- 

 trated in fig. 183 2 



Apex of abdomen without claspers (fe- 

 males) 6 



2. Clasper with upper portion elongated 



into a narrow, rounded, finger-like 

 lobe; ventro-mesal process of ninth 

 sternite long and projecting, e.g., 



obscura 3 



Clasper with upper portion short, 

 either pointed or rounded and 



blunt; ventro-mesal process of ninth 

 sternite short and triangular, e.g., 

 angustipennis, feria 4 



3. Aedeagus ending in a heavy, sclero- 

 tized hook; ventro-mesal process of 

 ninth sternite long and narrow. . . . 



obscura, p. 51 



Aedeagus ending in a pair of semimem- 

 branous lobes sclerotized at the 



179 



182 



Apex of Larval Frons 



Fig. 179. — Chimarra obscura. 

 Fig. 180. — Chimarra socia. 

 Fig. 181. — Chimarra feria. 

 Fig. 182. — Chimarra alerrima. 



SOCIA 



ANGUSTIPENNIS 





Fig. 183. — Chimarra, male genitalia. 



