THE CODLING MOTH IN MICHIGAN. 



73 



logical developments. In the course of the emergence period 

 part of the moths of the spring brood were hampered by cold rains, 

 which set in during the middle of June and caused a somewhat pro- 

 longed delay for about one-half of the moths. This irregularity in 

 the development of the insect produced an unusual effect upon the 

 tune and rate of occurrence of the separate stages for the rest of 

 the season. This is noticeable from a study of the curves of figure 

 21 for 1911. In the summer brood there occurred an abundance 

 of moths at the very start of the emergence, which was followed 

 by a decrease in number as a result of the delay found in the spring 

 brood; then again an abundance of moths appeared during the first 

 half of August as a result of the emergence of the later half of the 

 spring brood of moths. The prevailing high temperature advanced 

 the earliest developing insects to the extent that the second-brood 

 larva 1 appeared three weeks ahead of those of 1910, and further 

 prolonged to a very unusual extent the time of emergence of the 

 summer moths, the period of egg deposition, and the period of 

 hatching of the second brood of larva 1 . The large fruit crop, together 

 with the high temperature, favored the development of a large 

 second brood of larva*. For the total number of larvae collected at 

 the Douglas band records 50.5 per cent were of the tirst brood and 

 49.5 per cent of the second brood. 



Table LXXI. -Summary of results of hand records for 1909, 1910, and 1911, at Douglas, 



Mich. 



( Observations. 



Mollis emerging the same season 



Mnihs emerging the following season 



Total emergence of moths 



Wintering larvae of total band collection. . 



Wintering larva- killed by frost 



Parasitized larva- 



Relative proportion of first-brood larva-... 

 Relative proportion of second-brood larva- 



Transforming larva- of first brood 



Wintering larva- of first brood 



50.5 

 19. 5 

 34.9 

 65. 1 



The results from the band records for the three years at Douglas 

 show that of the first-brood larva about one-third transformed 

 the same season and two-thirds passed the winter in the larval stage, 

 as do all second-brood larvae. (Sec Table LXXI.) 



INSECT ENEMIES. 1 

 PREDACEOUS INSECTS. 



Several predaeeous insects have been found to attack the larvae 

 and pupae of the codling moth. Of these a small black beetle and its 

 larva, TenehrohU s corticalis Melsh, (PI. Ill, figs. 4. 5). belonging to 



1 For information relative to the bird enemies of the codling moth, see yearbook of the Department 

 of Agriculture for 1911, pp. 199-208, "Bird Enemies of the Codling Moth," by W, i. UcAtee. 



