240 



Illinois Natural History Survey Bulletin 



Fol. 23, Art. 1 



tion with sharp lateral extensions. . 



avara, p. 240 



Bursa copulatrix as in fig. 829, with 

 apex rounded and without sharp, 

 lateral extensions. . . .eddlestoni, p. 240 



15. Subgenital plate diamond-shaped, the 



posterior sides of the diamond 



raised and fencelike, fig. 830 



immobilis, p. 241 



Subgenital plate more vasiform, the 

 posterior sides of the vase folded 

 * laterad and shelflike, fig. 831 16 



16. Postero-lateral, shelflike margin ot 



subgenital plate nearly straight, the 

 anterior portion angulate and al- 

 most membranous, fig. 831 



inconspicua, p. 242 



Postero-lateral, shelflike margin of 

 subgenital plate arcuate, the an- 

 terior portion of the sternite more 

 ovate and distinctly sclerotized, fig. 

 832 ochracea, p. 244 



Oecetis avara (Banks) 

 Setodes avara Banks (1895, p. 316); cf. 



Larva. — Length 6.5 mm. Head, prono- 

 tum and legs straw color, top of head with 

 short brown bars. 



Case. — Length 7 mm., horn shaped, con- 

 structed of large sand grains cemented 

 together to form a fairly smooth exterior. 



Adults. — Length 10-11 mm. Color straw 

 yellow to light brown, the forewings with 

 numerous dark brown spots in the mem- 

 brane. Male genitalia, fig. 818: tenth ter- 

 gite short, slender and curved, consisting 

 of only a single mesal piece ; cerci short and 

 ovate; claspers somewhat kidney shaped; 

 aedeagus short and tubular, the apex slight- 

 ly expanded ventrad. Female genitalia, fig. 

 828, with ninth sternite wide, delineated by 

 arcuate dark lines, bursa copulatrix with 

 apex nearly truncate and basal portion with 

 sharp lateral extensions. 



Allotype, female. — Momence, Illinois: 

 Aug. 21, 1936, Ross & Burks. 



This species has been taken commonly in 

 the northern and central portions of the 

 state where it frequents fairly rapid streams 

 of various sizes. Larvae have been collected 

 and associated with the adults in the Galena 

 River at Council Hill, Illinois. The adults 

 emerge throughout the summer months from 

 May until early September. 



The range of the species covers most of 

 the United States, southern Canada and 

 Mexico. The spotting on the wings varies 



to a considerable extent, and it is possible 

 that the species disjuncta known from Cali- 

 fornia may be simply a color variant of this 

 species. We have records of avara from 

 Alabama, British Columbia, Georgia, Idaho, 

 Illinois, Indiana, Kentucky, Maine, Mary- 

 land, Michigan, Minnesota, Missouri, Mon- 

 tana, New Mexico, New York, Nova Scotia, 

 Ohio, Oklahoma, Ontario, Oregon, Penn- 

 sylvania, Tennessee, Texas, West Virginia, 

 Wisconsin and Wyoming. 



Illinois Records. — Many males and fe- 

 males and four pupae, taken June 5 to Sep- 

 tember 7, and many larvae, taken May 5 to 

 June 27, are from Apple River Canyon 

 State Park, Charleston, Council Hill (Ga- 

 lena River), Danville (Middle Fork River), 

 Homer, Kankakee (Kankakee River), Mo- 

 mence (Kankakee River), Oakwood (Mid- 

 dle Fork River), Oregon, Rock Island, St. 

 Charles, Serena (Indian Creek), Wilming- 

 ton, Yorkville (Fox River). 



Oecetis eddlestoni Ross 



Oecetis eddlestoni Ross (1938rt, p. 160); c?". 



Larva. — Length 5 mm. Head, pronotum 

 and legs straw color, the head with brown 

 bars and dots over most of its surface. 



Case. — Length 6 mm., constructed of sand 

 grains, with a fairly smooth exterior. 



Adults. — Length 10 mm. Color various 

 shades of light brown, without conspicuous 

 markings. Male genitalia, fig. 817: tenth 

 tergite consisting of a pair of stout, cylindri- 

 cal rods curved ventrad at apex, each bear- 

 ing two stout spines and reaching almost 

 to the apex of the claspers; cerci slender 

 and lanceolate; claspers short and somewhat 

 rhomboidal, the lower margin sinuate; aede- 

 agus with a slender basal stalk and a foot- 

 like apex. Female genitalia, fig. 829, with 

 the ninth sternite round, delineated by 

 curved lines, bursa copulatrix rounded at 

 apex and without lateral expansions at base. 



Allotype, female. — Serena, Illinois: June 

 16, 1939, along Indian Creek, B. D. Burks. 



We have collected this species in Illinois 

 only along Indian Creek at Serena, from 

 which locality the larvae were reared. It 

 was originally described from Pennsylvania; 

 we have additional records of this species 

 only from Illinois, Ohio and Oklahoma, so 

 that little can be said regarding its general 

 habits and distribution. 



Illinois Records. — Serena, Indian 



