August, 1944 



Ross: Caddis Flies of Illinois 



243 



and not very rigid in construction; a few 

 larger stones are frequently attached at 

 the sides. 



Adults. — Length 10-12 mm. Color brown 

 with a reddish cast, without distinct mark- 

 ings ; specimens in liquid showing a con- 



Fig. 834. — Oecetis inconspicua larva. 



spicuous dark bar across the cord. Position 

 of crossveins forming the cord extremely 

 variable, ranging from a condition in which 

 the three crossveins form an almost straight 

 line to one in which they are far removed 

 and steplike. Male genitalia, fig. 824: tenth 

 tergite forming a single, straight, fairly long 

 rod; cerci short and ovate; claspers with 

 dorsal margin incised to form a conspicuous 

 ventral lobe, their ventral margin somewhat 

 angulate at base; aedeagus almost circular, 

 with short beak. Female genitalia, fig. 831, 

 with ninth sternite membranous and not 

 bounded by dark lines, the apical shelf 

 straight and bursa copulatrix simple. 



This species is one of the most common 

 caddis flies in Illinois and has been taken 

 throughout the state. It is one of the few 

 caddis flies abundant in artificial ponds. 

 The larvae live in both lakes and streams. 

 They are seldom encountered in field col- 

 lections but are frequently present, together 

 with those of cinerascens, in fish stomachs. 

 The adults emerge throughout the warmer 

 months, from May until early October, and 

 frequently occur in immense numbers. 



The species is very widely distributed 

 throughout the North American continent 

 and appears to be fairly rare only in the 

 Northwest. We have records from Ala- 

 bama, Arkansas, British Columbia, Cali- 

 fornia, Cuba, Florida, Georgia, Illinois, 

 Indiana, Iowa, Kansas, Kentucky, Maine, 



Massachusetts, Mexico, Michigan, Minne- 

 sota, Missouri, Nebraska, New Brunswick, 

 New Hampshire, New York, Nova Scotia, 

 Ohio, Oklahoma, Ontario, Oregon, Penn- 

 sylvania, Quebec, Saskatchewan, South 

 Carolina, South Dakota, Texas, Utah, Vir- 

 ginia and Wisconsin. (See fig. 13.) 



Illinois Records. — Many males, females 

 and pupae, taken May 6 to October 10, and 

 many larvae, taken May 20 to August 7, 

 are from Algonquin, Alton, Amboy (Green 

 River), Antioch, Apple River Canyon State 

 Park, Bartonville (Kickapoo Creek), Brus- 

 sels, Cairo, Carbondale, Champaign, Chan- 

 nel Lake, Charleston, Chicago (roof of 

 Stevens Hotel), Clinton, Council Hill, Dan- 

 ville, Des Plaines, Downs, East Dubuque, 

 East Fox Lake, Eldorado, Elgin, Elizabeth- 

 town, Fieldon, Fox Lake, Frankfort (Hick- 

 ory Creek), Freeport, Galena (Sinsinawa 

 River), Galesburg, Golconda, Grafton, 

 Grand Tower, Grass Lake, Grayslake, 

 Hamilton, Hardin (Illinois River), Harris- 

 burg, Havana (Chautauqua Lake), Henry, 

 Herod, Homer, Jackson Island (Mississippi 

 River opposite Hannibal, Missouri), Jersey- 

 ville, Kampsville, Kappa (Mackinaw Riv- 

 er), La Rue (McCann Spring), Le Roy, 

 Libertyville, Liverpool, Mahomet, Mere- 

 dosia, McHenry, Milan (Rock River), Mo- 

 mence (Kankakee River), Montezuma, 

 Mount Zion (Fork Lake), Muncie, New 

 Memphis (Kaskaskia River), Oakwood 

 (Salt Fork River, Middle Fork Vermilion 

 River), Olive Branch (Horse Shoe Lake), 

 Ottawa, Palos Park (Mud Lake), Peoria, 

 Pontiac, Putnam (Lake Senachwine), 

 Quincy (stream near Cave Spring, Burton 

 Creek), Richmond, Ripley (Lamoine Riv- 

 er), Rockford, Rochelle, Rosiclare, Rome, 

 Round Lake, Savanna, Serena (Indian 

 Creek), Springfield (Sangamon River), 

 Spring Grove (Nippersink Creek), Starved 

 Rock State Park, Sterling, Urbana, Utica, 

 Venedy Station (Kaskaskia River), Wads- 

 worth (Des Plaines River), Waukegan, 

 White Pines Forest State Park, Wilming- 

 ton, Yorkville, Ziegler, Zion (Dead River). 



Oecetis persimilis (Banks) 



Oecetina persimilis Banks (1907rt, p. 129); 

 cf , 9. 



Larva. — Unknown. 



Adults. — Length 7-8 mm. Color light 

 brown, venter and legs straw color; wings 



