June, 1919] 



Fauna of Rock Bottom Ponds 



471 



The thirty year pond and the one a year old had almost the 

 same number of insect species, but it will be noticed that, 

 whereas in the youngest pond insects were abundant in both 

 species and individuals, in the oldest pond they were abundant 

 only in species. Furthermore, in the year old pond the species 

 with the greatest number of individuals were represented either 

 by pelagic adults or larval stages whereas in the thirty year pond 

 most of the species are shore forms. Both ponds had the same 

 number of species of adult beetles. Of the four present in 

 the thirty year pond only, at least three are usually to be found 

 among debris such as characterized the shore of this pond but 

 not that of the younger one. 



TABLE 24. 



Group 



Insecta 



Species 



Ponds 





o 



