L46 



THE AMERICAN NATURALIST [Vol. LI I 



as soon as the pond dries up. Amblystoma tigrmum de- 

 posits its eggs and then burrows into the mud and re- 

 mains ten months in estivation and hibernation. E'w- 

 branchipus deposits eggs that must be both dried and 

 frozen before hatching. Diaptomus stagnalis is similar 

 in character. Planaria velata forms cysts which live over 

 to the following spring. 



TABLE I 



Showing Seasonal Succession of Adult Spiders on a Low Prairie Sum- 



The species are arranged in the order of the seasonal occurrence of adults. 

 * indicates adults; young; e, eggs; g, generic identification only. C in- 

 dicates that the occurrence is creditable to Comstock and is not based upon 





5 ! 2 1 S | j 











lis 



TTIT 













Pardosa modica Blck * * 



. Tetragnatha laboriosa Htz \ gj \ * 



D ' Htz' * 



Pardota canadensis Blck \ gj \ j 



Lycosa heluo Wal ...... 



' -tdlata Htz [ \ 3 ..\. 3 .. 



















'266' 



26 

 160' 





i- 







Epeiratrvrittata Key 











... 



'.! ; ■ \\ 



M . • ■ • II'.: 



j'c 



fc 



jC jC 

 jC ,C 





* 



• 





)< ; 



eC 



; c 

 % 



"80* 



Phidippus audax Htz jC jC 



\ !. . . . C ;< ' 



jC 

 jC 

 3 



At the time these appear, land animals begin to move 

 about the pond margin, adult and juvenile spiders among 

 them. The collection and arrangement of the entire 

 fauna showed the same thing as the spiders, but proved 

 much less satisfactory in the other cases than was ex- 

 pected, owing to a lack of knowledge of life histories and 

 an inability to identify young stages. Turning to Table 

 I and following out the stars which indicate the occur- 



