166 FISHES OF ILLINOIS 



Males without tubercles or flushed coloration in spring. Females 

 much distended with eggs taken about first of June. 



This is one of our Illinois species whose distribution in the state 

 presents an ecological problem which we have no present means of 

 solving. Ranging from Lake Erie to the Black Warrior and the 

 Alabama southward, and to Iowa and Arkansas on the west, it oc- 

 curs abundantly in southeastern Illinois, but has been taken by us in 

 only two neighboring localities additional, one on the upper Kan- 

 kakee and the other on the Mackinaw. It is one of the species, in 

 fact, which has the appearance of spreading over the state from the 

 south and east mainly by the branches of the Wabash, but reaching 

 adjacent waters as if by overland migration. It is notably a species 

 of creeks, for which its frequency coefficient rises to the unusual 

 figure of 3.97. We have found it relatively about half as abundant 

 in the smaller rivers, and of only occasional occurrence in rivers of 

 the larger class. None of our 5 1 collections has been taken from 

 stagnant waters of any kind. 



HYBOPSIS STORERIANUS (Kirtland) 

 (stoker's chub) 



Kirtland, 1842, Proc. Bost. Soc. Nat. Hist., I, 71 (Rutilus). 



J. & G., 213 (Ceratichthys lucens) ; M. V., 65; J. & E., I, 321; N., 46; J., 56 

 (Alburnops); L., 19. 



A large species, known at once from our other species of Hyhopsis 

 by the double-rowed dark edging of the scales above the lateral line. 

 Length 5 or 6 inches; body elongate, considerably compressed; back 

 often somewhat elevated ; depth 4.3 to 5.3 in length ; caudal peduncle 

 rather slender, its depth 2 . 2 to 2 . 6 in head. Color translucent greenish 

 above, with purplish reflections; brilliantly silvery on sides and below; an 

 indistinct plumbeous lateral band, overlaid in life with emerald, below 

 which is a band of silvery to bluish blending with the silvery of belly; no 

 caudal spot and no vertebral streak; scales above lateral line, except a few 

 along middle of back in front of dorsal fin, each with two subparallel 

 rows of dark dots near posterior border, between which is a crescentic 

 lighter space; cheeks and opercles bright silver}^; fins plain, the dorsal and 

 caudal sometimes slightty dusky. Head 4.3 to 5.3 in length, compara- 

 tively short and compressed, cheeks nearly vertical; width of head 1 . 8 to 

 2; interorbital space entirely flat or somewhat concave, 3.3 to 3.5; eye 

 2.9 to 3.4 in head; preorbital bone especially prominent, large, oblong, 

 and silvery ; nose 2 . 8 to 3 . 1 , a little longer than eye, moderately decurved, 

 the tip of the muzzle somewhat thickened and pad-like, though not pro- 

 jecting much beyond mouth; mouth rather small, inferior and horizontal, 

 tip of upper lip far below level of lower margin of orbit; maxillary 3 . 2 to 



