152 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



some distance apart; the mesal margin is 

 nearly straight, the apex is rounded and 

 curved slightly dorsad, and near the lateral 

 margin is a sclerotized point midway be- 

 tween base and apex. Above the claspers 

 is a round plate bearing a pair of small 

 setae near the middle. Aedeagus with spiral 

 slender, neck large, and tip of apical portion 

 with a short lateral projection. Female, fig. 

 539: eighth segment semisclerotized, tubu- 

 lar, without internal plates or external 

 ornamentation; tergite with a fllat-bottomed 

 mesal depression; sternite with meson pro- 

 duced into a rounded lobe. 



Allotype, female. — Kankakee, Illinois: 

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



As pointed out in the lectotype designation 

 (Ross 1938c, p. 9), the type is in reality a 

 male, although the original description notes 

 it as a female. 



Our only Illinois records for this species 

 are from various points along the Kankakee 

 River (see p. 6). Here it is abundant; 

 we have taken larvae and pupae from the 

 river at Momence and Kankakee. Records 

 for the species are widespread but not nu- 

 merous, including Illinois, Indiana, Mis- 

 souri, Ontario and Wisconsin. All specimens 

 were taken along large, swift, clear rivers, 

 including the St. Lawrence, Kankakee, 

 White (in Indiana), Gasconade and White 

 (in Missouri), and Namekagon (in Wiscon- 

 sin). The adults emerge throughout the 

 warmer months (May through September). 



Records given under the name albicornis 

 by Betten (1934) probably refer to some 

 other species; the illustrations indicate 

 hamata. 



Illinois Records. — Kankakee: Kanka- 

 kee River, Aug. 1, 1933, Ross & Mohr, many 

 larvae; July 22, 1935, DeLong & Ross, 1 $ , 

 1 5 . Momence: July 14, 1936, B. D. Burks, 

 many pupae and larvae; Aug. 21, 1936, Ross 

 & Burks, S S, many pupae and larvae; 

 Kankakee River, Aug. 24, 1936, Ross & 

 Burks, 1 $ ; May 17, 1937, Ross & Burks, 



5 S , many pupae and larvae ; Kankakee Riv- 

 er, May 24, 1937, H. H. Ross, S $. Wil- 

 mington: Aug. 20, 1934, DeLong & Ross, 

 3 2 ; Kankakee River, May 17, 1937, Ross 



6 Burks, 2$ . 



Hydroptila scolops Ross 



Hydroptila scolops Ross (1938fl, p. 128); cf . 



Larva. — Unknown. 



Adults. — Size and color as for armata. 



Male genitalia, fig. 521: tenth tergite mem- 

 branous, divided into two large lateral lobes 

 and a small mesal lobe; claspers fairly long 

 and straight, with an apico-lateral sclero- 

 tized point and only small setae; aedeagus 

 short, basal portion flared, neck distinct, 

 spiral small and apical portion large at base, 

 tapering gradually to a pointed tip. Female 

 unknown. 



This species is known only from the holo- 

 type, collected along the Ohio River at 

 Shawneetown, Illinois, May 11, 1935, at 

 light, C. O. Mohr. 



Hydroptila angusta Ross 



Hydroptila angusta Ross (1938a, p. 130); cf , 



9. 



Larva. — Head and thoracic sclerites vary- 

 ing from tawny yellow to fairly dark brown, 

 the color fairly uniform over the entire area 

 and not forming a pattern. 



Adults. — Male, fig. 522: tenth tergite 

 wide, divided down meson by a deep, angu- 

 lar cleft, with only lateral margins sclero- 

 tized. Claspers with a wide "foot," the 

 upper portion bladelike; blade with a small, 

 sclerotized point on mesal margin beyond 

 middle, with a row of irregular setae on 

 lateral margin and with tip pointed. The 

 rounded plate above the claspers bears a 

 pair of short setae near apex. Aedeagus 

 very long, with an imbricated portion below 

 neck, a narrow neck, a long, stout spiral and 

 a long, slender apical portion which has a 

 sinuate, small finger at tip. Female, fig. 

 536: eighth segment semimembranous, ta- 

 pering; apex of tergite with a truncate in- 

 cision; sternite with somewhat stocky, mesal 

 plate near middle and with a mesal, tongue- 

 like projection at apex. 



Association of larvae and adults was 

 established by collections of larvae and pu- 

 pae from the Middle Fork River near Dan- 

 ville, and from other localities. 



In Illinois the species has been collected 

 from widespread localities. It prefers mod- 

 erate-sized to large streams and rivers, and 

 is frequently encountered in large numbers. 

 The adults emerge over a wide span; we 

 have records from May 1 to October 16. 



The range of the species extends from the 

 arid plains of western Texas and eastern 

 New Mexico to Ohio, with records from 

 Illinois, Indiana, Missouri, New Mexico, 

 Ohio, Oklahoma and Texas. 



Illinois Records. — Many males, females 



