THE CANKEEWORMS 



27 



Table 12.- 



■Length of larval feeding period of the spring cankerworm, Walling- 

 ford, Conn., 1921 — Continued. 



Date of hatching. 



Apr. 24. 

 Apr. 25 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 

 Apr. 26 



Do. 



Do. 



Do. 

 Apr. 27 



Do. 



Do. 



Date 



Num- 



Num- 



entered 



ber of 



ber of 



ground. 



larvae. 



days. 



June 4 



1 



41 



May 26 



1 



31 



May 27 



2 



32 



May 28 



1 



33 



May 29 



4 



34 



May 30 



3 



35 



May 31 



2 



36 



June 1 



1 



37 



June 5 



2 



41 



June 6 



1 



42 



May 29 



1 



33 



May 30 



2 



34 



June 4 



1 



39 



June 5 



1 



40 



May 30 



1 



33 



May 31 



1 



34 



June 1 



1 



35 



Date of hatching. 



Apr. 27. 



Do. 

 Apr. 28. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 

 Apr. 29. 



Do. 

 Apr. 30. 

 May 1.. 

 May 2. . 

 May 3. . 



Do. 



Date 

 entered 

 ground. 



June 4 

 June 5 

 May 28 

 May 29 

 May 30 

 May 31 



June 

 June 

 June 

 June 

 June 

 ...do- 



May 30 

 June 5 

 June 2 

 June 3 



Num- 

 ber of 

 larvae. 



Num- 

 ber of 

 days. 



Table 13. — Length of larval feeding period of the spring cankerworm, Walling- 

 ford, Conn., 1921. Summary of Table 12. 



Number 

 of days. 



Num- 

 ber of 

 larvae. 



Number 

 of days. 



Num- 

 ber of 

 larvae. 



Number 

 of days. 



Num- 

 ber of 

 larvae. 



Number 

 of days. 



Num- 

 ber of 

 larvae. 



Number 

 of days. 



Num- 

 ber of 

 larvae. 



29 



30 



31 



32 



1 



8 

 22 

 8 



33 



34 



35 



12 

 19 



7 



36 



37 



38 



3 

 3 

 2 



39 



40 



41 



3 

 2 



4 



42 



43 



44 



1 

 

 1 



Total larvae, 96. 



Average feeding period, 33. 7 days. 



Table 14. — Larval feeding period of the spring cankerworm, by stages, Walling- 

 ford, Conn., 1920 and 1921. 





1920 



1921 



Stage. 



Number 

 of larvae. 



Number 

 of days. 



Number 

 of larvae. 



Number 

 of days. 



First 



252 

 226 

 201 

 152 

 158 



7.75 

 3.73 

 3.66 

 5.66 

 5.31 



196 

 164 

 139 

 118 

 96 



9.87 





6.44 



Third 



5.19 



Fourth 



5.19 



"Fifth (to end of feeding) 



6.80 







Total feeding period 





26.11 





33.49 











ENTERING THE GKOUND. 



As with the fall cankerworm, the larvae enter the ground for 

 pupation to a depth varying from one to several inches. Only a few 

 threads of silk are spun in the pupal cell, and no cocoon is formed. 

 Table 15 gives the dates on which the larvse were entering the 

 ground in 1920 and 1921. 



