August, 1944 



Ross: Caddis Flies of Illinois 



67 



Allotype, female. — Same data as for 

 holotype. 



Paratypes. — New Hampshire. — Same 

 data as for holotype, 1 ? . 



New York.^ — Euba Mills, Adirondack 

 State Park: June 20, 1941, Prison & Ross, 

 \$. Varysburg: June 18, 1941, Prison & 

 Ross, 1 9 . 



This species is most closely related to cen- 

 tralis, from which it differs in the long, 

 arched, baso-dorsal lobe of the claspers, in 

 having the mesal angle of this point round, 

 in the widened tip of the aedeagus, and 

 other characters of the genitalia. 



Although not yet taken in Illinois, because 

 this species is fairly widely distributed in 

 the northeastern states, it may be taken here 

 in future collecting. 



Polycentropus cinereus Hagen 



PolycentropHS ci>ierens Hagen (1861, p. 293); 

 cf, 9.' 



Polycentropus catiadensis Banks (1897, p. 31); 



HolocentropHs flavicor}iis Banks (1907/^, p. 

 162); d^. 



Plectrocnemia pallescens Banks (1930i^, p. 

 231); cf , 9. 



Plectrocnemia lutea Betten (1934, p. 219); 

 cf , 9. 



Larva. — Pig. 230. Length 14 mm. Head, 

 pronotum and legs straw color, head and 

 sometimes pronotum with conspicuous 

 brown spots, those of the upper portion of 

 frons arranged in an angle; sometimes, also, 

 the dorsal part of head is suffused with 

 yellowish brown. Remainder of body pale, 

 without markings. 



Adults. — Length 7-9 mm. Color vari- 

 ous shades of brown, the wings mottled 

 with brown and light areas resulting in a 

 checkerboard mottling. Front and hind 

 wings with R., present. Male genitalia, fig. 

 240: tenth tergite short, stocky and semi- 

 membranous; cerci short and ovate; clasp- 

 ers appearing quadrate from lateral view, 

 the posterior margin incised to form a 

 dorso-mesal hook and a ventro-mesal lobe. 

 Female genitalia, fig. 261 : eighth sternite 

 short, lateral lobes large and somewhat 

 circular; ninth segment with its structures 

 membranous; bursa copulatrix dark, cone- 

 like and conspicuous. 



This species has been taken commonly in 

 all parts of Illinois. It is found in a wide 

 variety of situations, ranging from lakes to 



large rivers, showing a marked preference 

 for cool and clear water. Adult emergence 

 occurs from May to September. Larvae are 

 found chiefly under stones. Association of 

 larval and adult forms was established by 

 collections of all stages in Channel Lake. 



The range of the species is very wide, 

 occurring throughout the eastern states, 

 north and westward through Canada and 

 the northern states to the Pacific Coast 

 and extending southwestward through the 

 Ozarks to Oklahoma. We have records 

 from British Columbia, the District of Co- 

 lumbia, Illinois, Indiana, Kentucky, Maine, 

 Maryland, Michigan, Minnesota, Missouri, 

 New Brunswick, New Hampshire, New 

 York, North Carolina, Nova Scotia, Ohio, 

 Oklahoma, Ontario, Pennsylvania, Sas- 

 katchewan, South Dakota, Tennessee, 

 Washington and Wisconsin. 



Illinois Records. — Many males and fe- 

 males and seven pupae, taken May 24 to 

 September 20, and many larvae, taken May 

 5 to October 28, are from Algonquin, An- 

 tioch, Channel Lake, Danville (Middle 

 Pork River), Eddyville (Lusk Creek), El- 

 dorado, Elgin (Botanical Gardens), Fox 

 Lake, Galena (Sinsinawa River), Homer, 

 Johnsburg (Fox River), Kankakee (Kanka- 

 kee River), McHenry, Momence (Kan- 

 kakee River), Oakwood, Pontiac, Rich- 

 mond, Round Lake, St. Joseph, Serena 

 (Indian Creek), Spring Grove (Nippersink 

 Creek), Wilmington (Kankakee River), 

 Zion (Dead River). 



Polycentropus re wot us Banks 



Polycentropus remotus Banks (1911, p. 359); 



Larva. — Length 14 mm. Head, prono- 

 tum and legs straw color, the head with 

 well-marked spots. Upper portion of frons 

 subequal in length to lower portion, fig. 

 232. Body pale, without markings. 



Adults. — Length 7-9 mm. Color vari- 

 ous shades of brown with a checkered pat- 

 tern of small pale areas on the brown wings. 

 Both pairs of wings with R,, present. Male 

 genitalia, fig. 239: tenth tergite composed 

 chiefly of a pair of stocky, outcurved horns, 

 slightly expanded and provided with a short 

 spine at apex; cerci long and leaflike, the 

 upper portion produced into a lobe, and 

 the ventro-mesal corner bearing a stout, 

 heavily sclerotized projection curved ventrad 



