42 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Table XLI. — Length of life of male and female moths of the spring brood in captivity; 

 summary of records of 330 individual moths, Douglas, Mich., 1911. 



Table XLII. — Length of life of male and emale moths of the spring brood in captivity, 

 Douglas, Mich., 1911; summary of Table XLI. 



It is of interest to note that in this brood, as well as in the summer 

 brood, the females were more numerous than the males and survived 

 the males on an average by about two days. 



THE FIRST GENERATION 



FIRST BROOD OP EGGS. 



Length of incubation. — Observations on the length of incubation 

 extended over the greatest period when eggs occurred in the field 

 (Table XLIII). The high temperature which at times prevailed 

 brought the minimum length of incubation down to 4 days, against 

 6 days for the same brood in 1910. The average length of incubation 

 for the brood was 8 days, the maximum 10 days. Observations on 

 the embryological development of the eggs were also taken as recorded 

 in Table XLIII. The so-called "red ring" generally appeared 3 

 days after egg deposition, and the "black spot" 2 days previous to 

 hatching. 



