August, 1944 



Ross: Caddis Flies of Illinois 



151 



state; in the northeastern portion it inhabits 

 the glacial lakes and over the remainder it 

 inhabits a variety of clear streams and large 

 rivers. We have collections of larvae and 

 mature pupae from Fox Lake and from 

 Quiver Creek near Havana. Adult emer- 

 gence occurs from April through October. 



In addition to Illinois, the species is 

 known from Indiana, Michigan, Ohio, On- 

 tario, Saskatchewan and Wisconsin. 



Illinois Records. — Many males, females 

 and pupae, taken April 29 to October 5, 

 and many larvae, taken April 25 to May 29, 

 are from Amboy, Antioch, Council Hill, Fox 

 Lake, Galena, Grand Tower, Havana, 

 Kankakee, La Rue, Mahomet, McHenry, 

 Momence, Palos Park, Pere Marquette 

 State Park, Quincy, Richmond, Spring 

 Grove, White Pines Forest State Park, 

 Wolf Lake. 



Hydroptila delineata Morton 



Hydroptila delineatus Morton (1905, p. 66j; 



Not yet taken in Illinois; it is known from 

 Indiana, New York and Nova Scotia. Only 

 the male is known, readily distinguished by 

 the genitalia, fig. 518. 



Hydroptila grandiosa Ross 



Hydroptila grandiosa Ross (1938«, p. 126); 



Larva. — Fig. 508. Head tawny yellow 

 with dark posterior band and a dark V 

 across top of frons, this V sometimes closed 

 in front to form a dark, hollow diamond; 

 each thoracic tergum with an anterior light 

 margin and a pair of lateral light areas 

 outlined by a darker background. 



Adults. — Size and color as for armata. 

 Male genitalia, fig. 519: eighth sternite 

 large and scoop shaped, bearing four to six 

 black, peglike setae on each lateral margin; 

 ninth segment small and retracted within 

 eighth; tenth tergite divided into a pair of 

 large, sclerotized hooks broad at base and 

 sharp at tip; below these arise a pair of 

 long, sinuate rods around which the hooks 

 curl; claspers small, short and truncate; 

 aedeagus short, with a slender spiral and 

 tapered apex. Female genitalia, fig. 538: 

 eighth segment short, wide at base and nar- 

 rowing rapidly toward apex ; sternite with- 

 out external plates but with apex produced 



into a triangle set with short setae; internal 

 skeleton large and conspicuous, dark and 

 expanding anteriorly. 



Allotype, female. — Oakwood, Illinois, 

 along Salt Fork River: July 18, 1933, Ross 

 & Mohr. 



To date this species has been taken only 

 in the northern half of Illinois, in clear 

 rivers and small, permanent streams. In 

 only one or two cases have more than a 

 few specimens been taken at one time. The 

 adults emerge over the entire summer, our 

 records including May through September. 

 Larvae and both sexes of the adults were 

 associated by collections of larvae and pupae 

 from the Sinsinawa River near Galena, and 

 from the Apple River. 



Known from Illinois, Indiana, Missouri, 

 Oklahoma and Wisconsin, the species has a 

 range that seems to follow the better 

 streams of the western oak-hickory forest, 

 much as with armata. 



Illinois Records. — Amboy, Green River: 

 July 7, 1939, Mohr & Riegel, 2 ? . Apple 

 River Canyon State Park: Aug. 23, 1939, 

 Ross & Riegel, 1 $ ; Apple River, May 24, 

 1940, H. H. Ross, many larvae and pupae. 

 Danville, Middle Fork River: Aug. 27, 

 1936, Ross & Burks, \ $ , \ pupa, 4 larvae. 

 Galena: May 23, 1940, H. H. Ross, 2$, 

 3$, many pupae and larvae. Momence: 

 May 17, 1937, Ross & Burks, 1 $ ; Kanka- 

 kee River, May 24, 1937, H. H. Ross, 2$. 

 Muncie: June 27, 1932, H. H. Ross, 19. 

 Oakwood: Salt Fork River, July 18, 1933, 

 Ross & Mohr, 2 9 ; Salt Fork River, July 



18, 1933, Ross & Mohr, 2^,29; Salt Fork 

 River, Sept. 20, 1935, DeLong & Ross, 1 $ ; 

 May 21, 1936, Mohr & Burks, 1 pupa. 

 Richmond: Aug. 15, 1938, Ross & Burks, 



19. Rock City: June 6, 1940, Mohr & 

 Burks, \$. Sugar Grove: June 13, 1939, 

 Frison & Ross, \$ , 2 9. 



Hydroptila albicornis Hagen 

 Hydroptila albicornis Hagen (1861, p. 275); 



Larva. — Fig. 505. Head patterned with 

 pale yellow and dark brown, always with 

 a postero-mesal pale streak; each thoracic 

 notum dark brown with anterior margin 

 and a pair of lateral areas pale. 



Adults. — Male, fig. 520: tenth tergite 

 divided into a mesal and a pair of lateral 

 semimembranous lobes, each narrow. Clasp- 

 ers as long as tenth tergite, slender, situated 



