50 ILLINOIS BIOLOGICAL MONOGRAPHS [50 



fish inhabit the deeper water off the bars after the breeding season, but 

 are not as dependent upon weed beds as is the next species. On still, hot 

 days in mid-summer one often sees these fish at the surface, breaking water 

 in quest of insects of all sorts that have fallen upon the surface. Thus 

 I once took 8 honey bees from the stomach of a red-eye caught on a dry 

 fly in the middle of Oconomowoc lake when the fish were very evidently 

 up." The species is very voracious and largely piscivorous during 

 most of the summer, but toward fall the food changes to crayfish of which 

 they are inordinately fond. During September and October the stomachs 

 are packed with crayfish, often as many as 6 or 8 in a single alimentary 

 canal. They bite well on chubs (H. kentuckiensis and S. atromaculatus) , 

 shore minnows (any species of Notropis) and frogs (Rana pipiens), but 

 the best bait undoubtedly is "nightcrawlers" (Lumbricus terrestris). 

 They spawn on gravel bars, clearing out a depression 2 or 3 inches deep 

 in which the eggs are laid and over which the fish lies, gently fanning the 

 water to keep it in circulation. Any intruder is met by a furious rush and 

 either driven off or devoured. The young bass frequent the shallow water 

 along the edges of the lake, and are not at all confined to the presence of 

 weeds. In fact, in La Belle lake they are most abundant in water a foot 

 deep without a sign of vegetation. The young grow rapidly and reach a 

 length of about 3 inches by fall. Spawning occurs in May, but is hurried 

 or delayed by the temperature of the water, 65° to 68°F being the critical 

 temperatures in Waukesha county. The average size is 2\ pounds, but 

 I have taken specimens 5 to 5| pounds, these being about the maximum 

 size attained. An excellent table fish, second to none. 

 72. Micropterus salmoides (Lacepede). Large-mouth Black Bass; Green 

 Bass; Oswego Bass. 



By far the most abundant of the bass, inhabiting all of the lakes and 

 rivers. While the species is dependent upon bars for breeding purposes, 

 they are not particular, and any ledge two feet wide will do for the purpose. 

 This at once extends the possible distribution of the species over that 

 of the preceding. The green bass is also a fish of the deep water just off 

 of the bars, but those bars must be bordered by weed beds, usually Pota- 

 mogeton. In these weeds the fish lie, and into these weeds goes the fish 

 with any bait as quickly as possible. The average size is between 2 and 

 2\ pounds, though bass weighing 5 pounds and over are on rare occasions 

 caught. The largest of which I personally have a record which I know to 

 be authentic is 8j pounds, caught in Eagle lake. Between this enormous 

 fish and bass weighing 6 pounds I have no record. The fish breed in May 

 and if the season be backward are often still upon the beds by June 20 

 when the fishing season opens. These beds are shallow depressions well 

 up on the bars and, if the spawning space be limited, the nests are often 

 as close together as it is possible to put them. Over these beds the male 



