BIOLOGY OF MAYFLIES OF THE GENUS BAETIS. 



TABLE C 



Summary of Continuous Cycles, B. posticatus, at Ithaca, N. Y. 



Cycle 



Brood 1— May, 1918-October, 1918. . . . 

 Brood 2— October, 1918-August, 1919. 

 Brood 3— August, 1919-May, 1920. 

 Brood 4— May. 1920-October, 1920. . . . 



Months Av. Mon. Temp. 



607 

 47.9 

 41.4 

 62.2 



TABLE D 



Distinguishing Characters of Species of Baetis at Ithaca, N. Y. 

 Nymph Imago 



46 



