108 | DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 
that its development has been greatly influertced by the temperature. 
A cold spell was invariably followed by a delay in transformation, 
while a rise in temperature produced a corresponding hastening in 
development. 
COMPARATIVE LIFE-HISTORY STUDIES FOR THE SEASONS OF 
1907, 1908, AND 1909. 
On considering the records of the emergence of the moths (fig. 31) 
and the time of maturity and relative abundance of larve (fig. 32) 
for the three years under consideration, it is evident that the codling 
moth in its development is greatly influenced by seasonal conditions. 
way | aun 
es 5 10 ee 5 20 25 gi 5 10 15 aes ee 
bllosspme 
: if tT 
Fig. 31.—Time of emergence of spring-brood and first-brood moths, and the blossom periods of apple 
trees, during 1907, 1908, and 1909, at North East, Pa. (Original.) 
The cold and wet spring of 1907 limited the emergence of the spring 
moths to a short period. The oe low temperature delayed 
the larve to such an extent that only 3 per cent of the first brood 
transformed. The entire second generation was reduced to 3.5 per 
cent against 96.5 per cent of the first generation. 
The season of 1908 was evidently very favorable for the develop- 
ment of the codling moth. The early spring brought out the moths 
by May 25. During the long and warm summer the majority of the 
larve of the first brood transformed in great numbers (only 32.3 per 
cent wintered), and the following brood of larve attained a size equal 
to that of the first brood. 
