THE CODLING MOTH IN MICHIGAN. \) 



side against the celluloid more or less uncovered, so that the insects 

 could be observed within their cocoons without disturbing the latter. 

 Some larvae, however, particularly when exposed to too much light, 

 would line with silk the side of the cocoon against the film. The diffi- 

 culty in such cases was overcome by cutting in the film over the 

 cocoon a small lobe or flap which could be gently lifted for the neces- 

 sary exposure. This device is illustrated in figure 4. The upper 

 figure shows the lower side with numbers corresponding to the posi- 

 tion of the cocoons within. In the central figure several larvae and 

 cocoons are seen protected by the celluloid film. The two strips of 

 wood are held together by a pair of common paper clips which have 

 been bent and adjusted to the shape desired. 



13 lb IS 22 Z5 26 



April 



13 lb IS 22 25 28 31 



May 



3 6 4 12 15 18 21 24 



June 



Fig. 5.— Diagram showing time of spring pupation of the codling moth in 1910, at Douglas, Mich. ( Original.) 



Time of pupation. — Owing to the very warm weather during the 

 spring, pupation had commenced by April 15 (see fig. 5). However, 

 with a change to cold weather that followed, pupation was inter- 

 rupted until the latter part of May, and most of the larvae pupated 

 during the brief period from May 19 to May 31. The last pupa of 

 this brood appeared on June 23. (See Table V.) 



Table V. — Pupation period for the codling moth in the spring of 1910, at Douglas, Mich. 



No. of 



Date of 



No. of 



Date of 



No. of 



Date of 



No. of 



Date of 



larvae. 



pupation. 



larvae. 



pupation. 



larvse. 



pupation. 



larva?. 



pupation. 



2 



Apr. 15 



5 



May 25 



2 



June 4 



4 



June 14 



1 



Apr. 30 



3 



May 26 



2 



June 5 



3 



June 15 



1 



May 6 



2 



May 27 



1 



June 6 



2 



June 17 



4 



May 19 



9 



May 28 



2 



June 7 



2 



June 19 



1 



May 20 



8 



May 29 



2 



June 8 



1 



June 22 



21 



May 21 



4 



May 31 



1 



June 9 



2 



June 23 



14 



May 22 



1 



June 1 



4 



June 10 







13 



May 23 



2 



June 2 



3 



June 12 







5 



May 24 



2 



June 3 



1 



June 13 







