248 FISHES OF ILLINOIS 



the yellow perch (Perca) is practically unknown, the name of 

 perch is commonly given to these sunfishes — most frequently, 

 however, under the dialectic form of "pearch." 



Key to the Species of LEPOMIS found in Illinois 



a. Black opercular spot borne by the stiff bony upper posterior angle of the 



operculum, which is plainly distinguished from a flexible (fleshy or mem- 

 branous) border of different (usually lighter) color. (Fig. 60.) 



b. Mouth large and cheek not very deep, the maxillary % to % longer than the 



distance from the lower margin of the orbit to the lower posterior corner 

 of the preopercle; in life with blue spots and vertical bars of dusky; mar- 

 gin of ear-flap coppery to purplish; cheeks with wavy blue lines, .cyanellus. 

 bb. Mouth smaller and cheek deeper, maxillary about equal to or less than dis- 

 tance from lower margin of orbit to lower posterior corner of preopercle. 



c. Sides without longitudinal rows of spots formed by differently colored squar- 



ish areas (bronze or purplish in life) at centers of scales. 



d. Gill-rakers long, the longest y 2 diameter of eye; not mottled. 



e. Scales 41 to 49 in lateral line; margin of ear-flap pale blue to pinkish in 



life • • ischyrus. 



ee. Scales 32 to 37 in lateral line; in life green, barred with darker; small coffee- 

 colored specks on body and fins symmetricus. 



dd. Gill-rakers shorter, the longest scarcely more than % diameter of eye, usu- 

 ally less; mottled, the appearance being much as in the pumkinseed 

 sunfish (Eupomotis gibbosus) ; some red or coppery on ear-flap behind.... 



euryorus. 



cc. Many scales of sides with squarish light-colored areas (bronze or purplish in 

 life), these forming more or less distinct longitudinal rows; rest of body 



dusky olive • • miniatus. 



aa. Portion of opercular flap bearing black spot very thin and flexible. 



f. Bony portion of operculum terminating in front of the middle of the black 



opercular spot, which is confined chiefly to the broad pale (pinkish in life) 

 membranous (not osseous) border; in life olive with orange spots; cheeks 

 and opercles with wavy broken lines of rusty orange; no black blotch at 



base of last dorsal rays. (Fig. 63) humilis. 



ff. Bony portion of operculum continued backward as a thin and flexible 

 osseo-membranous flap, which is all or nearly all black, the longitudinal 

 bone-strise being visible through its ensheathing epidermis. (Fig. 62.) 



g. Gill-rakers short and weak, their length not over % eye; no black spot at base 



of last dorsal rays; olive with blue and orange spots and wavy vertical 



streaks of emerald; cheeks with wavy lines of emerald megalotis. 



gg. Gill-rakers rather long and slender, their length nearly % of eye; a black blotch 

 at base of last dorsal rays; life-color olive, with purplish luster. . pallidus. 



LEPOMIS CYANELLUS Eafine&que 



blue-spotted sunfish; green sunfish 



(Pl , p. 249) 



Rafinesque, 1819, Jour, de Physique, 420. 



J. & G., 473; M. V., 117; B., I, 21 ( Apomotis) ; J. & E., I, 996; N., 37 (Telipomis 



cyanellus and T. microps): J., 45 (Apomotis); F. F., I. 3, 47 (Apomotis); F., 



69; L., 25 (Apomotis); R., 27-32. 



Length 4 to 7 inches; body elongate, robust, becoming somewhat shorter 

 and deeper with age; dorsal outline rather more curved than ventral; depth 

 2.1 to 2.5 in length, usually about 2.2. Color olivaceous, taking on a yellow- 

 ish or coppery tinge below; each scale with a spot of emerald-green, the spots 



