PAPERS ON BIOLOGY AND AGRICULTURE 193 



GENERAL SURVEY OF THE FAUNA OF LAKE KNOX— Continued. 



Phylum Arthi-opoda — Continued 

 Order Isopoda 



Family Asellidae 



Asellus communis 



This was very common among decaying vegetable 

 matter of Station II and also of Station III. 

 They were found in puddles of the Muskrat 

 Region in early March while ice was still on. 

 Young ones were very numerous on the under 

 side of stones at Station I, May 28th. 

 Oniscus asellus 



The common sow bug was found in great num- 

 bers under bricks on the banks of Station I. 

 They are not really aquatic but live in damp 

 places. 



Order Decapoda 



Family Potamohiidae 



Cambarus propinQims 



This crayfish is found very frequently both In the 

 swift brick bottomed stream which enters the 

 pond and in the stream which flows into the 

 muskrat region. They bury themselves deep 

 down in the ground about the last of October. 

 Their holes or towers of mud are commonly 

 seen along the banks of the stream. We saw 

 them in the water again as early as March 2d. 

 In May the females bear young upon their swim- 

 merets. 

 Class Arachnoidea 



Water spiders were seen frequently swimming on the sur- 

 face of the water near Station I but none were identi- 

 fied. 

 Class Myriapoda 



A single milliped was found at Station I but was not 

 studied. 

 Class Insecta 



Order Ephemeridae 



No May-flies have been found. 

 Order Odonata 



Suborder Anispotera (dragon flies) 

 Macrcymia 



The nymph of this form was found on the bottom 

 at the north side of the pond near Station IV. 

 Libellula pulchella 



A nymph of this species was found several times 

 in the aquarium. 

 Suborder Zygoptera (damsel flies) 



Lestes nymphs were found among the Elodea of Sta- 

 tion IV. 

 A7}omalagrio7i 



A single nymph of this damsel fly was found. 

 Order Plecoptera (stone flies) 



A nymph was found under a brick at the incoming stream 

 but was not identified as to genus or species. 

 Order Hemiptera 



Suborder Heteroptera 



This group includes water bugs, skaters, water strid- 

 ers, and water boatmen. 



