53 



been subjected fails to show any very constant ratio between the two. 

 Under normal conditions the longest egg period recorded in the spring 

 was eight da3"s, and in the fall seventeen days. 



EFFECT OF REDUCED TEMPERATURES. 



Aside from the numerous records of the length of the egg period at 

 different temperatures under normal conditions, a few experiments 

 were made to ascertain the effect of much reduced temperatures on 



18 

 17 

 16 

 15 

 14 

 13 

 12 

 II 

 10 

 |8 

 58 



7 



6 



5 

 /I 



APR. 



MAY 



JUNE 



JULY 



AUG^ 



SEPT 



OCT 



NOV 



18 

 17 

 16 

 15 

 14 

 13 

 12 

 II 

 10 



9| 



8^ 



7 



6 



5 



4 



3 



2 



1 





































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r , 















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3 

 2 

 1 

 





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APR. 



MAY 



JUNE 



JULY 



AUG. 



SEPT. 



OCT 



NOV. 



Fig. 4.— Diagram showing relative length of q^z stage during season of 1904, Paris, Tex. (original). 



embryonic development. The first series consisted of six lots which 

 were placed in an ice-box where the temperature varied irregularly, 

 between 50° and 60° F. The appended table summarizes the results: 



Table XV. — Effect ofloiv temperatures on embryonic development. 



Num- 

 ber of 

 eggs. 



Age of Qgg. 



Time in 

 ice-box. 



Remarks. 



4 



1 

 428 



Brown ring present . . 



About to hatch 



Newlv laid 



Days. 

 13 



2 



lOi 



10 

 33 



13 



Eggs showed no development until removed, then hatched 



after 48 hours. 

 Egg showed no development until removed, then hatched 



after 3 hours. 

 A very few developed the brownish band, a few shriveled, 



and the greater portion remained white until removed, 



when they hatched after 2\ days. 

 Were dark at the end of 10 days and hatched on being 



taken out. 

 Eggs developed a wide brown band and became orange 



yellow; 12 hours after removal they darkened as if to 



hatch, but shriveled instead. 

 After 13 days many were hatching, while about 50 were 



hardly developed. 



Many. 



do 



600 



do 



382 



do 







The effect of much lower temperatures was tested at the Paris ice 

 factory, where the management very kindly placed at our disposal their 



