Entomology of the Illinois River. 153 



the sand by a small grassy and weedy slough, sparsely 

 grown with willows, through which the escaping spring 

 water makes its way to the river. This peculiar slough 

 is known as Station I. 



The three remaining stations are on the west side of 

 the river, in lakes which have no noticeable inflow of 

 percolating water: Phelps Lake, temporary in nature, 

 now open water, now dry, communicating with the river 

 only at rather high water, gives us Station F; Thomp- 

 son's Lake, large and permanent, with almost constant 

 river communication, mostly open water, affords us 

 Station G; and Flag Lake, a broad swampy expanse, 

 widely margined with club-rush (Scirpus), and with a line 

 of open ponds, is studied as Station K. 



The location of the different stations and their char- 

 acteristics at ordinary stages of water may be summa- 

 rized as follows: 



A. Junction of Quiver Creek and Quiver Lake; shallow, 

 mud and sand, grass and floating vegetation, variable. 



B. Wet springy shore of Quiver Lake; sand and mud, 

 grass and coating of alg£e. 



C. Near foot of Quiver Lake ; shores moderately slop- 

 ing and sheltered, the eastern sand and mud, the west- 

 ern mud, low, and wooded; water clear, with dense aquatic 

 vegetation, having little or no current in ordinary stages. 



L. Dogfish Lake; arm of Quiver Lake, shallow, very 

 gently sloping, mud, much floating vegetation, dead 

 water. 



E. River near Station C, somewhat narrow but deep 

 at middle; margin rather shallow, soft mud, little vege- 

 tation, current slight, bank wooded. 



D. Exposed shore of Havana Lake (a broadci' part 

 of river); moderately sloping, mud, considerable grass 

 and aquatic vegetation, very little current, not wood- 

 ed. 



H. Eiver below Havana, narrow, east bank steep and 

 sandy, a layer of mud over sand at lower levels, water 



