

732 



TEXTBOOK OP ZOOLOGY 



Fig. 382. — Total numbers of insects collected in average catch with 100 sweeps 

 of insect net in prairie ravine (Oklahoma). (Data from Carpenter.) The scale 

 for this graph is one-fourth of that in the preceding figure. 







c 



O 

 ■« 



A 



Jan. Fih. Alar Apr /^aj/ June 



JuU' 



Aaq 



Sepf-. Oci- 



Nov 



Dec. 



Fig. 383. — Fluctuations in populations of four Protozoa in an artificial lake 



(Oklahoma). (Data from Bragg.) 



