BIOLOGY OF MAYFLIES OF THE GENUS BAETIS. 



TABLE A 



Summary of Number and Length of Stadia, B. posticatus Laboratory Reared Specimens 



Stadium 



Days 



Length Body 



Per Cent. Death Rate 



TABLE B 



Summary of Corresponding Yearly Cycles, B. fosticatus, at Ithaca, N. Y. 



Cycle 



May, 1918-October, 1918~ 



May, 1919-October, 1919 



May, 1920-October, 1920 



August, 1918-May, 1919 



August, 1919-May, 1920 



October, 191'8-August, 1919 



October. 1919-August, 1920 



(1) 376 Specimens. (2) 237 Specimens. 



45 



Months Av. Mon. Temp. 



