112 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



apex; tenth tergite short, the apical lobes 

 somewhat ovate, somewhat polished, and 

 appressed on the diagonal to the apex of 

 the tergite. 



This species is common in small streams 

 of the northern fourth of the state, in the 

 vicinity of Oalcwood and also in the center 

 of the western margin of the state. 



The species shows a decided preference 

 for brooks and small creeks, especially those 

 fed by springs and permanent in character. 

 The only exception we have to this is a col- 

 lection from Oregon, Illinois, which pre- 

 sumably came from the Rock River. The 

 adult emergence extends from May to late 

 September. 



The range of the species is poorly deline- 

 ated. In addition to Illinois records we have 

 only one from Indiana and two from the 

 heart of the Ozarks in western Arkansas. 



Illinois Records. — Many males and fe- 

 males and 1 pupa, taken May 11 to Sep- 

 tember 20, are from Apple River Canyon 

 State Park, Cedarville, Charleston, Che- 

 mung, (Piscasaw Creek), Danville (Middle 

 Fork River), Deer Grove, Elgin, Galena 

 (Sinsinawa River), Homer, Howardsville, 

 Mahomet, Mount Carroll, Muncie, Oak- 

 wood, Oregon, Quincy (stream near Cave 

 Spring), Rock City, Serena, Sycamore (trib- 

 utary of South Kishwaukee River), Urbana, 

 White Pines Forest State Park. 



C heutnatopsyche analis (Banks) 

 Hydropsyche analis Banks (1903^, p. 243); 



Hydropsyche pettiti Banks (1908^, p. 265); cf. 



Adults. — Length 9-12 mm. Color vary- 

 ing from almost entirely dark brown with 

 few light spots on the wings to a lighter 

 phase with many small, light spots and the 

 two anal spots as described for burksi. Male 

 genitalia, fig. 400: claspers with apical seg- 

 ment long, slightly sinuate and pointed; 

 tenth tergite with apical lobes projecting 

 slightly in front of mesal angle of tergite, 

 low, and with the apex widened into a some- 

 what round plate which is nearly truncate 

 at apex ; these plates vary considerably in 

 proximity to each other. 



A re-examination of the type of analis 

 convinces me that the curious structure of 

 the tenth tergite of the type is due to me- 

 chanical injury, to wit, the breaking off of 

 the apical lobes. The ridging of the tenth 

 tergite, narrow aedeagus and shape of the 



claspers leave no doubt in my mind that this 

 is the same as pettiti, in which type the 

 genitalia are intact. In the type of analis, 

 the caudal aspect of the tenth tergite is 

 asymmetrical and appears to end dorsad at 

 fracture lines. 



This species exhibits the interesting phe- 

 nomenon of a dark color phase correlated 

 with the earliest spring emergence and suc- 

 cessively lighter color forms as the season 

 advances into warmer weather. The same 

 phenomenon is shown to a certain extent 

 by other caddis flies, but I have observed 

 none in which it is as marked as in this 

 species. 



In Illinois the species is very widespread. 

 It shows a preference for small streams 

 but occurs also in the larger rivers. With 

 campyla, it is often found in streams carry- 

 ing considerable pollution and in which few 

 or no other caddis flies are found. It has a 

 wide ecological tolerance. 



The range of the species is extremely 

 large, extending from the Atlantic to the 

 Pacific through the northern states and 

 from Georgia and Oklahoma in the south 

 to Minnesota, Ontario and New Hampshire 

 in the north. 



Illinois Records. — Many males and fe- 

 males, taken April 16 to September 20, are 

 from Amboy, Apple River Canyon State 

 Park, Aurora, Baker (Indian Creek), Bour- 

 bonnais (Rock Creek), Cedarville, Charles- 

 ton, Chemung (Piscasaw Creek), Chester- 

 ville, Clinton (Weldon Springs), Cora, 

 Crescent City, Danville, Dixon Springs, El- 

 gin (Botanical Gardens, Rainbow Springs), 

 Erie, Freeport, Gibson City, Gilman, Green- 

 up (Embarrass River), Halfday, Harris- 

 burg, Havana (Quiver Creek), Herod, 

 Homer, Horse Shoe Lake, Howardsville, 

 Kankakee, Kappa (Mackinaw River), Le- 

 land, Mahomet (Sangamon River), Ma- 

 rengo, Mazon (Mazon Creek), McHenry, 

 Momence (Kankakee River), Monticello, 

 Morris, Mount Carroll, Muncie, Oak Hill, 

 Oakwood, Oregon, Ottawa, Palos Park 

 (Mud Lake), Pontiac, Quincy, Richmond, 

 Rock City, Savanna, Serena (Indian Creek), 

 Spring Grove (Nippersink Creek), Starved 

 Rock State Park, Sycamore (tributary of 

 South Kishwaukee River), Urbana (Salt 

 Fork River), Utica (Split Rock Brook), 

 Wadsworth (Des Plaines River), Wauke- 

 gan. West Vienna, White Heath, White 

 Pines Forest State Park, Wilmington (Kan- 

 kakee River), Yorkville (Fox River). 



