August, 1944 



Ross: Caddis Flies of Illinois 



103 



Hydropsyche hageni Banks 



Hydropsyche hageni Banks (1905;^, p. 14); 



Larva. — Fig. 353. Length 15 mm. Head 

 and thoracic sclerites brown, legs yellowish 

 brown; head with lateral and posterior por- 

 tions yellowish, limiting the dark brown of 

 the dorsum to a broad T of which the cross- 

 piece is broad and rather sharply cut off 

 laterally; the brown T area of head and 

 all of the pronotum finely granulate with 

 paler marks. Frons flat, its apical margin 

 straight, the area surrounding the anterior 

 portion of the fronto-genal suture set with 

 abundant, short, black spines. 



Adults. — Length 10-11 mm. Color dark 

 brown, the wings mottled with various 

 shades of brown and typical of the common 

 pattern of the scalaris group, as in fig. 393. 

 Eyes of male large, each equal to the area 

 between them on the dorsum. Male geni- 

 talia, fig. 374, with tenth tergite short and 

 pointed slightly ventrad; aedeagus with 

 straight stem and with lateral processes 

 greatly elongated, flattened and almost 

 truncate at tip. Female readily distin- 

 guished from other species of the scalaris 

 group by the thickened lateral lobe of the 

 ninth tergite, fig. 386Z). 



Allotype, female. — Momence, Illinois: 

 May 17, 1937, Ross & Burks. 



Our Illinois records of this species are 

 confined to the Kankakee River, with the 

 exception of male specimens taken along the 

 Rock River. Along the Kankakee we have 

 taken it consistently but always in small 

 numbers and have found the larvae and 

 pupae in the rapids. The adults have been 

 taken from May to late August. 



The range of the species is poorly delin- 

 eated. Our only records are from Illinois, 

 Kentucky and Maryland. These indicate 

 a marked preference for large, rapid rivers. 



Illinois Records. — Kankakee: June 12, 

 1931, Frison & xMohr, \$ ; June 6, 1935, 

 Ross & Mohr, 1 $ ; May 6, 1938, Ross & 

 Burks, 9$ ; May 31, 1938, Burks & Mohr, 

 \$. Momence: May 26, 1936, H. H. 

 Ross, $ $ , (y larvae; Aug. 3, 1936, C. O. 

 Mohr, 1 $ ; Aug. 4, 1936, Frison & Burks, 

 3 $ ; May 24, 1937, H. H. Ross, 1 $ ; May 

 5, 1938, Ross & Burks, 4 5, 3 larvae; Oct. 

 28, 1938, Ross & Burks, 2 larvae; preced- 

 ing Momence records from Kankakee Riv- 

 er; Aug. 21, 1936, Ross & Burks, 2$, 1 

 pupa; May 17, 1937, Ross & Burks, 1 i 



pupa, S $ , 15,4 larvae; May 5, 1938, Ross 

 & Burks, 4 5, 3 larvae; Aug. 16, 1938, 

 Ross & Burks, 1 $ ; June 24, 1939, Burks 

 & Ayars, \$. Rockford: June 12, 1931, 

 Frison & Mohr, 1 $ ; May 30, 1936, H. H. 

 Ross, \$. Wilmington, Kankakee River: 

 June 6, 1935, Ross & Mohr, 1 $ . 



Hydropsyche placoda Ross 



Hydropsyche placoda Ross (194U, p. 87); 

 cT, 9. 



Larva. — Unknown. 



Adults. — Length 10-11 mm. General 

 color typical for most members of the sca- 

 laris group, the male differing in having 

 the eyes reddish and the wings slightly light- 

 er. Eyes of male very large, each one equal 

 to the dorsal area between them and almost 

 completely hiding the head from side view. 

 Male genitalia, fig. 375, with tenth tergite 

 somewhat beaklike ; apical segment of clasp- 

 ers short and markedly truncate; aedeagus 

 of fairly uniform thickness, the lateral proc- 

 esses triangular from side view and dorsal 

 margin almost confluent with the stem, and 

 the mesal cavity more than half closed. 

 Female with small eyes; genitalia, fig. 3865, 

 distinguished by the pit at dorsal portion of 

 clasper groove. 



In Illinois this species has been taken in 

 numbers only near the dam on the Illinois 

 River at Starved Rock State Park. Other 

 records are represented by few specimens. 

 We have not yet obtained larvae, but it is 

 probable that they occur in the race below 

 the dam at Starved Rock State Park. 



This species has been taken in many of 

 the north central states and as far east as 

 Niagara Falls. In addition to this New 

 York locality, we have records from Illinois, 

 Minnesota, Montana, South Dakota and 

 Wisconsin. 



Illinois Records. — Elgin : Botanical 

 Gardens, June 6, 1939, Burks & Riegel, 

 1 c5 ; Rainbow Springs, June 6, 1939, Burks 

 & Riegel, 15- Kankakee: June 12, 1931, 

 Frison & Mohr, \$. Ottawa: June 3, 

 1938, Mohr & Burks, 15- Richmond: 

 June 7, 1938, at light, Ross & Burks, 1 5 . 

 Rockford: June 29, 1938, at light, B. D. 

 Burks, 25. Rock Island: June 23, 1928, 

 at light, Frison & Hottes, 1 5 ; June 24, 

 1931, at light, C. O. Mohr, 15. Serena: 

 Fox River, June 3, 1938, Ross & Burks, 

 3 5 . Starved Rock State Park: June 28, 

 1937, G. T. Riegel, 9 5,2$; June 28, 1937, 



