THE CANKERWORMS 



13 



NUMBER OF LARVAL STAGES. 



Some writers have reported five larval stages for the fall canker- 

 worm, but all larvae under observation at Wallingford have invari- 

 ably entered the ground at the close of the fourth instar. 



LENGTH OF FEEDING PERIOD. 



Table 3 gives the larval feeding period for 165 larvae from 6 egg 

 masses in 1919 and for 106 larvae from 5 egg masses in 1920. These 

 data are summarized in Table 4, in which it will be noted that a 

 larva may complete its development in as short a time as four weeks, 

 or it may require nearly six. Practically all of them, however, com- 

 pleted their feeding in from 30 to 35 days, and in both seasons the 

 average was slightly over 32 days. 



Table 3.- 



-Length of larval feeding period of the fall cankerworm, Wallingford, 

 Conn., 1919 and 1920. 



FOR 165 LARViE FROM 6 EGG MASSES, 1919. 



Date of hatching. 



May 1. 

 Do 

 Do 

 Do 

 Do 



May 2. 

 Do 

 Do 



May 3. 

 Do 

 Do 



May 4. 

 Do 

 Do 

 Do 

 Do 



Date en- 

 tered 

 soil. 



June 

 June 

 June 

 June 

 June 

 June 

 June 

 June 

 June 

 June 

 June 

 June 

 June 

 June 

 June 



June 6 



Num- 

 ber of 

 larvae. 



Number 

 of days. 



Date of hatching. 



May 4. 

 Do 

 Do 

 Do 



May 5. 

 Do 

 Do 

 Do 



May 6. 

 Do 

 Do 

 Do 

 Do 



May 7. , 

 Do 



Date en- 



Num- 



tered 



ber of 



soil. 



larvae. 



June 7 



3 



June 8 



1 



June 10 



2 



June 11 



1 



June 4 



6 



June 5 



8 



June 6 



26 



June 7 



2 



June 5 



7 



June 6 



16 



June 7 



5 



June 9 



2 



June 10 



1 



June 6 



2 



June 10 



1 



Num- 

 ber of 

 days. 



FOR 106 LARV^ FROM 5 EGG MASSES, 1920. 



May 11 

 Do 

 Do 

 Do 

 Do 



May 12 

 Do 

 Do 

 Do 

 Do 

 Do 



May 13 

 Do 

 Do 

 Do 



June 10 



2 



30 



June 11 



13 



31 



June 12 



4 



32 



June 14 



2 



34 



June 15 



3 



35 



June 12 



1 



31 



June 13 



4 



32 



June 14 



6 



33 



June 15 



7 



34 



June 16 



1 



35 



June 20 



1 



39 



June 12 



14 



30 



June 13 



10 



31 



June 14 



6 



32 



June 15 



7 



33 



May 13 

 Do 

 Do 

 Do 

 Do 



May 14 

 Do 



May 15 

 Do 



May 16 

 Do 

 Do 



May 17 

 Do 

 Do 



June 16 



1 



June 17 



1 



June 19 



1 



June 20 



1 



June 23 



1 



June 14 



5 



June 15 



3 



June 15 



3 



June 16 



1 



June 16 



2 



June 18 



1 



June 23 



2 



June 16 



1 



June 19 



1 



June 22 



1 



