68 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



at apex; claspers appearing quadrate from 

 lateral view, with a slender, digitate dorso- 

 mesal projection. Female genitalia, fig. 260: 

 eighth sternite short, its lateral lobes large, 

 almost quadrate, and close together along 

 meson, covered with short setae ; ninth 

 sternite with a pair of distinctive, small, 

 quadrate sclerotized plates which are nar- 

 rowed and pointed at apex ; other internal 

 structures membranous or irregular. 



Allotype, female. — Zion, Illinois, along 

 Dead River: June 6, 1940, Mohr & Burks. 



As with flavus, this species has been taken 

 in Illinois chiefly along the Dead River, 

 and our main collection is a series of larvae, 

 pupae and adults taken along with the 

 allotype. This species is widely distributed, 

 occurring from the Atlantic to the Pacific. 

 So few collections are known, however, 

 that a very local distribution is indicated. 

 Records are available from British Colum- 

 bia, Illinois, Minnesota, New Hampshire 

 ind New York. 



Illinois Records. — Richmond: June 4, 

 1938, Ross & Burks, 2$. Spring Grove: 

 Aug. 12, 1937, at light, Ross & Burks, 1 9 . 

 ZiON, Dead River: June 3, 1938, Mohr & 

 Burks, 1 $ ; June 6, 1940, Mohr & Burks, 

 2$ , 4 2, 3 larvae. 



Polycentropus nascotius Ross 



Polycentropus nascotius Ross (1941^, p. 

 73); cf . 



Not yet taken in Illinois, but to be looked 

 for in future collecting. It is a rare species 

 with a wide distribution, known from New 

 Brunswick, Nova Scotia and Wisconsin. 



Polycentropus flavus (Banks) 

 Holocentropus flavus Banks (1908^, p. 66); 



Larva. — Length 14 mm. Head somewhat 

 uniformly reddish brown of a dusky shade, 

 the typical spots present but inconspicuous, 

 being almost the same color as the ground 

 color. Pronotum and legs yellowish brown. 

 Remainder of body pale without markings. 



Adults. — Length 7-9 mm. Color brown 

 with a checkered pattern on the wings 

 similar to that of nascotius. Front wings 

 with R^ present, hind wings with R., absent. 

 Male genitalia, fig. 237: tenth tergite with 

 a pair of very long, curved sclerotized rods 

 following the curve of the aedeagus; cerci 



fairly long and narrow, the apex provided 

 with a short, appendage-like prolongation; 

 claspers with a high lobe at base, apex nar- 

 row and rounded ; at the top of the lobe is 

 a small, triangular flap projecting mesad, 

 and below this there is frequently a tooth- 

 like projection. Female genitalia, fig. 250: 

 eighth sternite long, slightly incised at apex, 

 and extending well beyond the lateral lobes, 

 which are narrow and pointed; between 

 them the eighth sternite is raised into a 

 pyramid, sloping sharply at the sides. 



Allotype, female. — Zion, Illinois, along 

 Dead River: June 6, 1940, Mohr & Burks. 



Our only recent Illinois records are from 

 the extreme northeastern portion of the 

 state. The two sexes and immature stages 

 were associated by a series of males, fe- 

 males, pupae and larvae collected at Zion 

 in and along the Dead River (see p. 12). 



The species has been recorded over a wide 

 but scattered range, probably indicating a 

 very local distribution. Records are avail- 

 able from Illinois, Newfoundland, New 

 York and Ontario. 



Illinois Records. — Urbana: May 17, 

 1887, C. A. Hart, \$, 1 $ ; May 19, 1887, 

 C. A. Hart, U , 2 2 ; May 20, 1887, C. A. 

 Hart, 1 2 ; June 20, 1888, Forbes, Marten 

 & Hart, 1 2 . Zion, Dead River: May 20, 

 1940, Mohr & Burks, 2 larvae; June 6, 

 1940, Mohr & Burks, \$, 32. 



Polycentropus glacialis (Ross) 



Holocentropus glacialis Ross (1938a, p. 135); 



Larva. — Length 13 mm. Head, pronotum 

 and legs yellowish, the head frequently 

 with slight brownish suffusions; spots on 

 head distinct, the two major setae on upper 

 part of frons surrounded by a small brown 

 area. Remainder of body without mark- 

 ings. 



Adults. — Length 8-9 mm. Color, gen- 

 eral structure and venation similar to those 

 of flavus. Male genitalia, fig. 238: tenth 

 tergite composed of a pair of long, curved, 

 sclerotized rods; cerci narrow and spatulate, 

 without an appendage; claspers appearing 

 somewhat quadrate from lateral view, the 

 dorsal margin curved over into a trapezoidal 

 flap projecting meso-ventrad. Female geni- 

 talia, fig. 252: eighth sternite with fairly 

 short, ovate, lateral lobes which are wide 

 apart at base ; between them is a wide, 

 transverse ledge without abrupt apical mar- 



