Entomology of the Illinois River. 155 



stations in Quiver, Dogfish, and Tiiompson's lakes (A, 

 B, C, L, and (i), and D, in the broader part of the 

 river, are situations of the above description. 



Station A has no definite shore, but because of its 

 shallowness exhibited many features of shore life, and 

 varied greatly as the real mouth of the creek shifted up 

 and down with the changes in the height of the river. 

 Aquatic caterpillars found food here, and horse-fly and 

 crane-fly larvae lived in the mud ; certain case-flies were 

 more common because of the running water; soldier-fly 

 larvae (Stratiomyiidae), well protected by their tough 

 skin, found appropriate food; and predaceous bugs and 

 beetle larvae also abounded. Surface-beetles (Gyrinidae) 

 were seen only now and then as single examples, and the 

 larger surface-bugs or water-striders (Hydrobatidae) were 

 never very numerous, though the smaller ones (Veliidae) 

 were often seen on the floating vegetation in immense 

 numbers. Water-beetles, except the haliplids, were as a 

 rule comparatively few, seeming to prefer grassy margins 

 and sticks and logs. Chironomid larvae were abundant 

 in the vegetation and the mud of the bottom. Top- 

 minnows were seen gliding about in the little clear spaces; 

 leeches and mollusks were plentiful. 



At Station C the life was quite similar to the above, 

 but the muddy west shore, often flooded and washed bare 

 by the river, seemed inhospitable to shore-loving forms, 

 beetles and dipterous larvae of this class being noticeably 

 few, although small surface-bugs, stratiomyiid larvae 

 and aquatic caterpillars were common in the abundant 

 vegetable growth. The nenropteroid forms were here 

 unusually abundant. 



The shore of Thompson's Lake at Station G, although 

 ■exposed, was protected during the summer by a belt of 

 algae and "moss" (Ceratophyllum etc.) and diffei-ed from 

 the west side of C in its sandy shore, favorable to the 

 development of dipterous larvae generally, horse-fly larvae 

 and Stratiomyiidae often abounding m the rubbish 



