August, 1944 



Ross: Caddis Flies of Illinois 



37 



hind legs pale yellow. Abdomen with an 

 irregular purplish pattern. 



Adults. — Fig. 134. Length 10-12 mm. 

 Head, body and legs various shades of light 

 and medium brown; f ronto-dorsal area of 

 head with a distinct, dark, quadrate spot; 



Fig. 134. — Rhyacophila fenestra 9. 



wings fenestrate with light and dark brown. 

 Male genitalia, fig. 126, with short, beaked 

 tenth tergite; claspers short, the apical seg- 

 ment incised; aedeagus with a central scoop- 

 like structure and lateral processes. Female 

 genitalia as in fig. 131, eighth segment sim- 

 ple in shape. 



This species, known only from Illinois, is 

 with one exception restricted to the Ozark- 

 ian area, where it is abundant in all the 

 clear, rapid streams, most of them flowing 

 only in winter and spring. 



The one exception is a single colony of 

 fenestra located in a small, temporary 

 stream at Oakwood. 



Illinois Records. — Many males, females 

 and pupae, taken April 21 to June 6, and 



many larvae and cases, taken March 23 to 

 May 26, are from Aldridge, Alto Pass, Car- 

 bondale, Dixon Springs, East Peoria, Eddy- 

 ville, Eichorn, Elizabethtown, Golconda, 

 Herod (Gibbons Creek), Jonesboro, Kar- 

 bers Ridge, New Columbia (Clifty Creek), 

 Oakwood, Vienna, Wolf Lake. 



Rhyacophila ledra Ross 



Rhyacophila ledra Ross (1939«, p. 65); d^. 



Similar to fenestra in color and general 

 structure, differing in characters of the 

 male genitalia, fig. 127, particularly the 

 apical segment of the claspers, the lateral 

 arms of the aedeagus and the humped cen- 

 tral ridge of the aedeagus. To date, char- 

 acters have not been found to separate the 

 larvae or females of these two species. 



Our sole Illinois record for this species 

 consists of two fully matured male pupae 

 collected in Union Spring, a small, tempo- 

 rary stream near Alto Pass in the Ozark 

 Hills of southern Illinois, May 26, 1940, 

 Mohr & Burks. The species is known other- 

 wise only from the type material collected 

 in Tennessee. 



Rhyacophila kiatnichi new species 



Male. — Length 9 mm. Color dark brown 

 with very little mottling, the wings with 

 only slight indications of an irrorate pat- 

 tern. General structure typical for genus. 

 Male genitalia, fig. 125: ninth segment 

 cylindrical, considerably narrowed near ven- 

 tral margin, tenth tergite composed of a 

 pair of dorsal lobes which are round, pro- 

 ject over the rest of the tergite, and bear 

 a short, sclerotized tooth on the posterior 

 margin; below this is a group of small 

 sclerites very similar to those in other mem- 

 bers of the Carolina group; claspers with 

 basal segment very wide at base, the ventral 

 margin conspicuously angulate just beyond 

 base and curving gradually to a narrowed 

 apex ; apical segment of clasper with dorsal 

 corner rounded and short, posterior mar- 

 gin only slightly concave, the ventral por- 

 tion of the segment wide and rounded at 

 apex, the mesal face with an irregular pe- 

 ripheral brush of short, flat setae arranged 

 as illustrated; aedeagus very similar to that 

 of fenestra, with a sharp, dorsal, keel-like 

 structure divided at apex into dorsal and 

 ventral prongs, ventral portion large and 

 scoop shaped, and lateral arms membran- 



