No. 628] HABITAT RESPONSES OF WATER-STRIDER 395 



I. Introduction 

 Thk large water-strider, aerris rcuiigis Say (Fis:. 1), 

 is one of our most intorosting and familiar acinatic hugs. 

 Diiriiio- the years VM') iDclusive, \ made a somewliat 



iiUcnHve Mudy cf tlu' ivHinii-r. (,r tl:i^ -^pr.-ir^ to the 

 pli\>ical coiiditioii^ ..f it^ ..nx^ionmrnt. in tlic viritiitx n[ 

 rrbaiia, IJliiiois. Tlii> MiuIn lia^ lir. ii .-niit imird. inter- 

 mittently, u]) to the ]jreseiit time. Tiif piociit puMica- 

 tion forms only a part of tlif entire iiixcvt i^at ions. 

 Part of this paper treats of ol»si'i'\at ions m.-idr n>ar 

 Ilrhana, Illinois, and ])ai-t treats of oUservat ions made 



