434 Illinois State Laboratory of Natural Jlistonj. 



voracious, with a wonderfully distensible stomach; and not 

 only captures the most active fishes, such as the pike, but will 

 eat carrion, and may even swallow stones. It is reported to be 

 nocturnal in habit, and often to secure its prey by stealth. 



It is illustrated in our collection by ten examples; five 

 taken in spring and five in November. All but one had eaten 

 fishes, these making eighty-three per cent, of the food of the 

 entire group. One of the spring specimens had taken cray- 

 fishes only — Camharus ijropinquus^ the species commonest in 

 the lake. Two others of this lot had likewise eaten crayfishes, 

 fifty per cent, of the food of one and fifteen per cent, that of 

 the other consisting of this same species. The fishes taken, 

 with the exception of one young white-fish ( Coregonus dupei- 

 formis) and a small unrecognizable residue, were the common 

 perch of the lakes, Perca lutea. 



FAMILY ESOOID^. 



This family is represented within our limits by the Euro- 

 pean species, Esox lucius (the so-called common "pickerel" of 

 the streams and smaller lakes of Illinois), by the noble muskal- 

 lunge, Esox nohilior of Lake Michigan, and by the small grass 

 pickerel, Esox umbrosus. No fishes of our waters, unless it be 

 the gars, have become so strictly adapted to a predaceous life, 

 — an adaptation which probably limits them, nolens volens, to 

 a living prey. 



Esox LUCIUS, Linn. Pike ; Pickerel. 



Our specimens of this species, thirty-seven in number, of 

 nine different lots, were from various parts of the Illinois 

 River, except a single one from Fourth Lake in northern Illi- 

 nois. 



One had eaten larvge of dragon flies (twenty per cent.), but 

 the entire food of the remainder consisted only of fishes, these 

 making, consequently, ninety-nine per cent, of the whole. 

 Nine per cent, were not otherwise recognizable. Twenty-one 

 per cent, were sunfishes and black bass — one of the latter the 

 small-moathed species — and nine per cent, were croppie (Po- 



