172 



ILLINOIS STATE ACADEMY OF SCIENCE 



were taken from this level. The remaining strata con- 

 sidered were the shrub, herb, and ground strata. Be- 

 cause of the constant presence in the forest of a blanket 

 of leaves on the surface of the soil, the ground stratum 

 was divided, for the purpose of this study, into two parts 

 which will be referred to as the leaf and soil strata. Of 

 the latter only the upper ten centimeters were considered. 



Week 

 No. 



5 



Aug. 1 



10 



Sept. 5 



20 15 



Nov. 14 Oct. 10 



Fig 1. 



25 30 



Dec. 19 Jan. 23 



35 

 Feb. 27 



40 

 Apr. 3 



45 50 



May 8 June 12 



The unit of sample from the soil and leaf strata was 

 taken from an area two feet square. The unit sample 

 from the herb and shrub strata was that obtained by ten 

 short sweeps through the vegetation with an insect net 

 whose subcircular opening averged thirty centimeters in 

 diameter. It is not claimed that there is an exact cor- 

 respondence in the numerical data as obtained from the 



