August. 1944 



Ross: Caddis Flies of Illinois 



207 



Adults. — Length 16 mm. Body and ap- 

 pendages various shades of brown and gray, 

 the wings with light areas in the middle 

 forming a more or less checkered pattern. 

 Male genitalia, fig. 706: tenth tergite some- 

 what hood shaped, produced into a short, 

 rounded beak at apex ; claspers with a small 

 basal portion which merges gradually into 

 a long, apical blade; at the extreme base of 



Fig. 710. — Molanna uniophila, case. 



the clasper there arises a short, mesal, flat 

 process bearing short setae at its apex; 

 aedeagus tubular and slightly curved, con- 

 taining an eversible group of long spines. 

 Female genitalia very simple, bursa copu- 

 latrix small and without complicated struc- 

 tures. 



In Illinois this species has been collected 

 only in the glacial lakes and connecting 

 streams in the northeastern part of the 

 state. In these localities the larvae are 

 found on gravel bars where they may occur 

 in large local colonies. Our adult records 

 are all for May and June, indicating a 

 single generation per year. 



The curious case of this insect has been 

 the cause of frequent remarks by students 

 of aquatic insects. Vorhies reared this spe- 

 cies from Wisconsin, and we have reared 

 it from Channel Lake, Illinois. 



The range of the species is extensive 

 through the Northeast. Records are avail- 

 able for Michigan, Minnesota, New Bruns- 



wick, New York, Ohio, Pennsylvania, Que- 

 bec and Wisconsin. 



Illinois Records. — Antioch : July 1, 



1931, Frison, Betten & Ross, 1 $ ; July 6, 



1932, Frison et al, 6$ ; June 11, 1936, Ross 

 & Burks, $$,99; June 12, 1936, Ross & 

 Burks, 2$, 19. Channel Lake: May 

 16, 1936, Ross & Mohr, many pupae which 

 were reared, adults emerging June 1-3, 

 1936, Urbana; May 27, 1936, H. H. Ross, 

 $ $, ? 9, many pupae, larvae and cases; 

 May 31, 1938, Mohr & Burks, 1 larva. 

 Fourth Lake, Lake County: Aug. 2, 1887, 

 C. A. Hart, \$. Fox Lake: June 30, 



1935, DeLong & Ross, $ $ , 9 9; May 28, 



1936, H. H. Ross, 3 $ ; June 10, 1936, Ross 

 & Burks, \ $ , 19. Grass Lake: July 14, 

 1926, Frison & Hayes, 1 $ . Johnsburg, 

 Fox River: May 28, 1936, H. H. Ross, 

 t? 5, 39. Round Lake: June 26, 1936, 

 at light, Frison & DeLong, $ $ , 9 9. 

 Sand Lake: June 17, 1893, Hart & Shiga, 

 \$. South Chicago: June 9, 1880, \$. 

 ZiON, Dead River: May 20, 1940, Mohr 

 & Burks, 2 larvae. 



Molanna musetta Betten 



Molanna musetta Betten (1934, p. 248); d". 



Larva. — Unknown. 



Adults. — In size, color and general struc- 

 ture similar to uniophila. Hind wing with 

 a long, arcuate, conspicuous furrow of scales 

 running from the apical corner down below 

 the middle and to the base of the wing, hg. 

 708. Male genitalia almost identical with 

 uniophila, the tenth tergite with the dorsal 

 portion larger, fig. 704. 



We have only one record of this species 

 for Illinois, a male collected along the Kan- 

 kakee River at Wilmington, August 20, 

 1934, DeLong and Ross. This species appar- 

 ently has a scattered range through the 

 Northeast with a southwestward extension 

 through the Ozarks into Oklahoma. We 

 have records from Illinois, New York, 

 Oklahoma and Ontario. 



Molanna tryphena Betten 



Molanna tryphena Betten (1934, p. 248); 



Not yet taken in Illinois. This species 

 occurs in Michigan, New York and Wis- 

 consin. Dr. Betten (1902) has reared it 

 in New York, recording it as cinerea. 



