50 



Illinois Natural History Survey Bulletin 



Fol. 23, Art. 1 



sides; ventro-mesal process of ninth 



tergite shorter and spatulate 



socia, p 



4. Ventral margin of claspers produced 

 into a slightly upturned lobe 



angustipennis, p 



Ventral margin of claspers not pro- 

 duced, forming a rounded lobe 

 e.g., feria 5 



51 



51 



OBSCURA 



SOCIA 



ATERRIMA 



Figs. 184-187. — Chimarra, female genitalia. 

 A, ventral aspect; B, bursa copulatrix; C, dorsal 

 aspect. 



5. Claspers with caudal face flat, trans- 



verse dorsal spur straight and dorsal 

 shoulder projection small or lacking 



aterrima, p. 50 



Claspers with caudal face excavated, 

 transverse dorsal spur curved basad 

 and dorsal shoulder projection high 

 and triangular feria, p. 50 



6. Ninth tergite constricted sharply near 



apex, fig. 185 socia, p. 51 



Ninth tergite with lateral margins 

 straight to apex 7 



7. Ninth sternite produced into well- 



defined, lateral, sclerotized "ears"; 

 bursa copulatrix with only a single, 

 delicate, U-shaped sclerite, fig. 184 



obscura, p. 51 



Lateral margin of ninth sternite with- 

 out lateral extensions; bursa copu- 

 latrix with at least a complete sclero- 

 tized ring, figs. 186, 187 8 



8. Sclerite of bursa copulatrix ringlike, 



with a circular central clear area, 



fig. 187 feria, p. 50 



Sclerite of bursa copulatrix purselike, 

 with a semicircular central clear 

 area, fig. 186 aterrima, p. 50 



Chimarra aterrima Hagen 



Chimarrha aterrima Hagen (1861, p. 297); c?', 

 9. 



Our only Illinois records for this species 

 are from small, spring-fed brooks in the 

 northern fourth of the state. Our records 

 are from April and May, indicating a single 

 generation per year in Illinois. In northern 

 states the species has been collected through- 

 out the summer months. 



This species is very abundant throughout 

 the eastern states, fig. 17, with records from 

 Florida, Illinois, Indiana, Kentucky, Maine, 

 Michigan, Minnesota, New Brunswick, 

 New York, North Carolina, Nova Scotia, 

 Ontario, Pennsylvania, Tennesse, Virginia, 

 West Virginia and Wisconsin. Illinois ap- 

 pears, therefore, to be on the western limit 

 of its main range. It has been collected 

 farther west only once, at Malvern, Arkan- 

 sas. 



Illinois Records. — Council Hill, trib- 

 utary of Galena River: April 9, 1941, Ross 

 & Mohr, many larvae. Dundee: May 23, 

 1939, Burks & Riegel, $ $ , ? $ , many 

 larvae. Utica, Split Rock Brook: May 

 24, 1941, \$. 



Chimarra feria Ross 



Chimarrha feria Ross (1941^, p. 51); c?', 9. 



This species is very common in many of 

 the rapid clear streams in the Ozark region 

 of southern Illinois. Most of these streams 

 are dry during the summer and autumn 

 period. In these dry situations we have col- 

 lected larvae of this species in a normal, 

 active, healthy condition under stones in por- 

 tions of the river bed which were damp be- 

 neath the surface. The adults are among 

 the earliest caddis flies to appear on the 

 wing in this state, having been found at 

 Herod as early as March 28. 



The range of the species embraces rough- 

 ly the western edge of the oak-hickory forest 

 region, fig. 17. Records are available from 

 Arkansas, Illinois, Kansas, Minnesota, Mis- 

 souri, Oklahoma, Texas and Wisconsin. 

 Illinois is on the extreme eastern edge of 

 its range. 



Illinois Records. — Dixon Springs: July 

 9, 1935, DeLong & Ross, 1,3. Golconda: 



