110 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



Lateral invagination much longer and 

 larger, usually approximate to pos- 

 tero-ventral point of segment, figs. 

 407-413 14 



14. Lower margin of lateral invagination 



forming a wide, round lobe extend- 

 ing below postero-ventral corner, 

 and with posterior corner upturned 

 and level with anterior corner, fig. 



408 aphanta, p. Ill 



Lower margin of lateral invagination 

 either concave, fig. 411, or with 

 anterior corner much higher than 

 posterior corner, figs. 409, 410, 

 never forming the rounded ventral 

 lobe as above 15 



15. Lateral margin of ninth tergite pro- 



duced into a narrow, ventral angular 

 point in which the lateral invagina- 

 tion ends and which projects slightly 

 beyond the postero-ventral corner, 



fig. 409 oxa, p. 110 



Lateral margin not forming a ventral 

 angular projection, fig. 410 16 



16. Lateral invagination with inner open- 



ing on mesal side, fig. 410 



speciosa, p. 1 14 



Lateral invagination with inner open- 

 ing on posterior side, figs. 411-413 17 



17. Lateral invagination with lower pos- 



terior corner situated a short dis- 

 tance from postero-ventral corner of 



segment, fig. 407 analis, p. 112 



Lateral invagination with lower pos- 

 terior corner nearly touching pos- 

 tero-ventral corner of segment, fig. 

 411 18 



18. Lateral invagination elongate and 



curved at apex, the two approxi- 

 mate on meson, fig. 413. . . .lasia, p. 114 

 Lateral invagination shorter and not 

 curved at apex, fig. 411 19 



19. Lateral invagination smaller, the two 



divergent and very far apart, fig. 



411 campyla, p. 113 



Lateral invagination larger, the two 

 parallel and closer together, fig. 412 

 pasella, p. 113 



Cheumatopsyche sordida (Hagen) 



Hydropsyche sordida Hagen (1861, p. 290); 

 d', 9. 



Adults.— Length 6-8 mm. Head and 

 body various shades of brown; antennae 

 paler with a brown V-mark on the seven 

 basal segments of the flagellum; wings uni- 

 formly dark brown without pattern. Male 

 genitalia, fig. 394, with apical segment of 

 claspers short and stubby; tenth tergite 



wide, the mesal portion rounded with the 

 apical lateral corners produced into short, 

 flat, truncate lobes. 



In Illinois we have taken this species only 

 at Wilmington, along the Kankakee River. 

 This is apparently along the western limits 

 of the species' range; this range includes 

 the denser portions of the beech-oak-hick- 

 ory forest, with extensions southwestward 

 through the Ozarks and neighboring ranges. 

 Records are available from Arkansas, Illi- 

 nois, Indiana, Kentucky, Michigan, Mis- 

 souri, New York, Pennsylvania, Quebec 

 and Wisconsin. Adults emerge from May 

 to September. 



Illinois Records. — Wilmington, Kan- 

 kakee River: May 27, 1935, Ross & Mohr, 

 $ $, $9,1 mating pair, 1 larva; June 6, 

 1935, Ross & Mohr, 1 U , 8 ? ; July 1, 1935, 

 DeLong & Ross, \ $ , 1 ? . 



Cheumatopsyche minuscula (Banks) 



Hydropsyche minuscula Banks (1907«, p. 

 130); d^, 9. 



This species has not yet been taken in 

 Illinois but may eventually be found here. 

 It is similar to sordida in its dark coloring 

 and has a somewhat similar range, being 

 known from Arkansas, Georgia, Kentucky, 

 New York, Oklahoma, Ontario, Quebec, 

 Tennessee and Wisconsin. 



The tenth tergite and short apical seg- 

 ment of the claspers of the male distinguish 

 the species from others in the genus. 



C heumatopsyche oxa Ross 



Cheumatopsyche oxa Ross (1938^, p. 155); 

 cf , 9. 



Adults. — Length 8-9 mm. Color uni- 

 formly dark brown with only a few incon- 

 spicuous light areas near the anal angle of 

 the wings. Male genitalia, fig. 396, with 

 apical segment of the claspers very long, 

 slender and pointed; apical lobes of tenth 

 tergite, from caudal view, appearing fairly 

 long, narrowed near middle and slightly 

 widened at tip. 



In Illinois, we have three scattered rec- 

 ords of this species, each along a small, 

 spring-fed stream. These and records from 

 other states show the adult emergence to 

 extend from March to middle or late Octo- 

 ber. Records from other" states also indi- 

 cate a preference for small, rapid streams, 



