374 



SCIENCE 



[N. S. Vol. XLAai. No. 1215 



TABLE II 



Average Animal Population for Twenty-day Periods 



TABLE ni 



Bevised Animal Population 



variation in abundance in all orders of ani- 

 mals in any two examinations, and it is only 

 by averaging results for twenty-day periods 

 that some idea can be gained of seasonal vari- 

 ation. 



Tbe great unevenness in the Ortboptera 

 and Homoptera columns is because each indi- 

 vidual grasshopper or mealybug egg is 

 counted as an individual. The result is to 

 greatly increase the apparent total animal 

 population i^ the fall and early spring. But 

 when each cluster of eggs is counted as one 

 individual, the Orthoptera become negligible 

 and the Homoptera decrease in numbers from 

 early fall, the resulting total animal popula- 

 tion showing a very striking uniformity 

 throughout each season. 



The one third increase in population in the 

 spring over that in the autumn is due, not to 

 insects, but almost entirely to earthworms and 

 sowbugs — the earthworms being most abundant 

 early in the spring when the ground is moist. 



and going deeper than six inches as it later 

 dries out, but the sowbugs become most abun- 

 dant in May. Variations in the Hymenoptera 

 column are due to occasional accidental selec- 

 tion for examination of a plot containing a 

 nest, or near a nest of ants, but variations in 

 the numbers of beetles, of which many species 

 in greatly varying abundance were found, can 

 not be assigned to any one cause. Consider- 

 able numbers of empty puparia were found, 

 quite out of proportion to the small number 

 of live Diptera. Thysanura were very abun- 

 dant when weather conditions were just right, 

 but Lepidoptera (mostly cutworms) and 

 Hemiptera showed quite uniform abundance. 

 The data as a whole show the preponderating 

 abundance of earthworms, sowbugs, beetles, 

 spiders and ants in this particular habitat. 



George N. Wolcott 



1539 Sunset Ave., 

 Utica, N. Y. 



