August, 1944 



Ross: Caddis Flies of Illinois 



245 



are known from onh' a limited number of 

 localities. Eight species have been taken in 

 Illinois, of which one is represented by an 

 unidentified female. The specific characters 

 of the female sex have been worked out 

 sufficiently to show that this unidentified 

 eighth species is different from the other 

 seven taken in the state. 



fuscous area to form lines, fig. 838. . 4 

 Lateral portion of head mostly pale; 

 pronotum with only small dark 



areas marginata, p. 251 



Lateral portion of head mostly dark 

 with pale lines between the dark 

 areas; pronotum almost entirely 

 dark, fig. 838 species b, p. 253 



KEY TO SPECIES 

 Larvae 



1. Head with pale antennae and with a 



pattern of spots, only a few anterior 

 ones somewhat coalesced to form 



weak lines, fig. 835 tarda, p. 250 



Head with definite lines reaching pos- 

 terior portion of head, fig. 836, or 

 antennae black 2 



2. Head lines broken into spots at pos- 



terior portion, fig. 836; pronotum 



without extensive dark areas 



injusta, p. 252 



Head lines solid to posterior margin of 

 head, fig. 837; pronotum usually 

 with dark patches in addition to dark 

 spots on posterior portion 3 



3. Lateral spots of head distinct and 



separate, fig. 837 aba, p. 249 



Lateral spots of head connected b)' a 



Adults 



L Genitalia with claspers and aedeagus, 



figs. 839-850 (males) 2 



Genitalia without these structures, 

 figs. 851-861 (females) 13 



2. Claspers consisting chiefly of a thin, 



vertical plate, incised on apical mar- 

 gin, fig. 839 3 



Claspers consisting of a solid base the 

 mass of which is distributed hori- 

 zontally, and often bearing various 

 lateral or mesal lobes, figs. 841-850 4 



3. Inner spur of clasper long, curved and 



whiplike, fig. 839 frontalis, p. 249 



Inner spur of clasper short, somewhat 



angular and stocky, fig. 840 



grisea, p. 249 



4. Tenth tergite forming a long fork, with 



a basafstalk, figs. 841, 842 5 



Tenth tergite single or vestigial, fig. 

 843 6 



■''■!w:«i'-|;l(llll;i:'"' 



838 



836 



Fig. 835.-7. tarda. 

 Fig. 836.— T. injusta. 



Larvae of Triaenodes 



Fig. 837.— 7\ aba. 

 Fig. 838.— r. species b. 



