158 



Illinois Natural History Survey Bulletin 



Vol. 23. Art. 1 



of sand grains woven into an even, fairly 

 smooth surface. Top opening closed for 

 pupation by an irregular silky layer. 



Adults. — Length 1.5-2.0 mm. Color 

 strawlike, wings with only indistinct mark- 

 ings. Male genitalia, fig. 547: tenth ter- 

 gite large, bilobed and submembranous; ven- 

 tral plate (probably consisting of the fused 

 claspers) large, clothed with long setae and 

 narrowed and upturned at apex; aedeagus 

 with a large spiral process at neck, the api- 

 cal portion submembranous with one or two 

 accessory finger-like lobes. Female genitalia, 

 fig. 554: eighth sternite practically color- 

 less, divided down meson by membranous 

 incision which flares out at the base; within 

 this area at the base arises an ovate struc- 

 ture with rounded apex and membranous 

 base; bursa copulatrix with long, slender, 

 apical style and a pair of horns at its base. 



Allotype, female. — Kankakee, Illinois : 

 July 22, 1935, at light, DeLong & Ross. 



No record of this species, the smallest 

 known caddis fly in North America, has 

 been published since its original description 

 from Covington, Kentucky. It is the com- 

 monest species of the genus in Illinois, espe- 

 cially abundant in the upper Sangamon 

 River, where we have reared it, and has 

 been taken also from the Kankakee River 

 and a few small streams. 



The species is known to range through 

 Missouri, Oklahoma, Illinois, Indiana and 

 Kentucky. 



Illinois Records. — Kampsville: July 2, 

 1931, Prison, Betten & Ross, 1 $ . Kanka- 

 kee: Kankakee River, Aug. 1, 1933, Ross & 

 Mohr, 1 S ; July 22, 1935, at light, DeLong 

 & Ross, 2S , 19. Mahomet, Sangamon 

 River: June 6, 1940, Ross & Riegel, 2 pu- 

 pae. Oakwood, Middle Fork River: Sept. 

 7, 1936, DeLong & Ross, 1 5 . Quincy, 

 Burton Creek: June 25, 1940, Mohr & 

 Riegel, 1$. Urbana: Aug. 3, 1931, light 

 trap, W. P. Flint, 7 6 . White Heath : 

 Aug. 2, 1940, Ross & Riegel, 1 ? . 



Neotrichia okopa Ross 



Neotrichia okopa Ross (1939,^, p. 629); cf , 9. 



Adults. — Length 2 mm. Body and ap- 

 pendages dark brown, the wings mottled. 

 Male genitalia, fig. 546: tenth tergite mem- 

 branous with a mesal lobe, a pair of long 

 setae and a pair of lateral extensions; be- 

 neath it are a pair of sclerotized processes; 



lateral appendages spatulate; aedeagus with 

 a very long, cylindrical, basal portion, nar- 

 row neck with a prominent spiral process 

 and the apical portion more or less cylin- 

 drical and heavily sclerotized. Female geni- 

 talia, fig. 556: eighth sternite with sclero- 

 tized portions forming a dark V; above the 

 base of the V is a small, rounded structure 

 the base of which is divided into two lobes; 

 bursa copulatrix as in fig. 5565. 



This species, not previously recorded from 

 Illinois, has been taken at only widely sep- 

 arated localities in the state. It was espe- 

 cially abundant in Lusk Creek in the Ozark 

 Hills, where it was reared in company with 

 collata and riegeli. Its known range includes 

 scattered localities in Illinois, Ohio, Okla- 

 homa and Pennsylvania. Our collecting in 

 Illinois indicates its preference for small, 

 clear streams. 



Illinois Records. — Apple River Can- 

 yon State Park: Aug. 23, 1939, Ross & 

 Riegel, 1 $ . Council Hill, Galena River: 

 June 26, 1940, Mohr & Riegel, \$, many 

 pupae. Eddyville, Lusk Creek: June 19- 

 20, 1940, Mohr & Riegel, $ $ , 9 5. Mo- 

 mence: June 22, 1938, Ross & Burks, 8^. 

 Utica, Split Rock Brook: June 17, 1941, 

 Burks & Riegel, $ $ , 9 9. White Pines 

 Forest State Park: Aug. 13, 1937, Ross 

 & Burks, \$, 9 9. Wilmington: July 

 1, 1935, DeLong & Ross, 1 9. 



Neotrichia kitae Ross 



Neotrichia kitae Ross (1941^, p. 60); d^, 9. 



To date this species has not been taken 

 in Illinois. It is known only from Hollister, 

 Missouri. This species resembles the others 

 of the genus in general size and shape, but is 

 readily distinguished on the basis of geni- 

 talia, figs. 542, 553. 



Neotrichia edalis Ross 



Neotrichia edalis Ross (1941^, p. 62); cf, 9. 



Although not yet taken in Illinois, this 

 species frequents streams in eastern Okla- 

 homa which are very similar to some in 

 southern and western Illinois and may possi- 

 bly be taken in the state in the future. The 

 genitalia of both sexes, figs. 549, 550, are 

 diagnostic for the species; the triangular 

 subgenital plate of the female eighth sternite 

 is unusual in the genus and distinctive. 



