10 



BULLETIN 901, U. S. DEPARTMENT OF AGRICULTURE. 



Table IV. — Time and duration of larval feeding period of A. chalybea, North East, Pa., 



1917. 



Date of 

 hatching. 



Date of 

 entering 

 ground. 



Number 

 of larvse. 



Duration 

 of period. 



Date of 

 hatching. 



Date of 



entering 

 ground. 



Number 

 of larvse. 



Duration 

 of period. 



June 4 

 12 

 13 

 13 

 13 

 14 

 14 

 14 

 14 

 15 

 15 

 16 

 16 



June 28 



July 1 



4 



5 



8 



7 



8 



9 



17 



11 



13 



8 



10 



2 

 1 

 2 

 1 



4 

 1 

 2 

 2 

 1 

 2 

 2 

 1 

 1 



Days. 

 24 

 19 

 21 

 22 

 25 

 23 

 24 

 25 

 33 

 26 

 28 

 22 

 24 



June 17 

 17 

 17 

 19 

 19 

 19 

 19 

 19 

 20 

 20 

 20 



Julv 8 

 10 

 11 

 10 

 11 

 13 

 14 

 20 

 15 

 17 

 20 



3 



1 



2 



4 



1 



Days. 

 21 

 23 

 24 

 21 

 22 

 24 

 25 

 31 

 25 

 27 

 30 



146 



2 24. 26 



i Total. 



2 Weighted average. 



1917. 



DURATION OF SECOND LARVAL STAGE. 



The duration of the second stage, of 60 larvse reared, varied from 

 5 to 11 days with an average of 6.95 days, as show^n in Table VI. 

 m v „. , 7 7 , , The total period covered by records on 



Table V. — First larval stage of r . J 



A. chalybea, North East, Pa'., larvae of this stage extended from June 9 



to July 8. 



DURATION OP FEEDING PERIOD OP THIRD LARVAL 

 STAGE. 



The duration of the feeding period of 

 the third stage, of 47 larvse reared, varied 

 from 5 to 13 days with an average of 

 8.53 days, as is shown in Table VII. The 

 total period covered by records on larvae 

 of this stage extended from June 15 to 

 July 20. 



DURATION OP PERIOD IN GROUND. 

 weighted average. The duration Q f the period in the groxmd 



varied from 15 to 25 days with an average of 19.24 days. The total 

 period covered by records on the immature stages in the ground and 

 emergence are given in full in Table VIII. 



DURATION OF PREPUPAL PERIOD. 



The duration of the prepupal period, of 23 individuals recorded, 

 varied from 7 to 13 days with an average of 9.17 days, as shown in 

 Table IX. The period covered by records on prepupae extended 

 from June 28, when the first larvae entered the ground, to July 24, 

 when the latest transformed to pupae. 



DURATION OF PUPAL PERIOD. 



The duration of the pupal period of 17 individuals recorded 

 varied from 7 to 10 days with an average of 8.47 days, as shown in 

 Table X. Records on this stage extended from July 17 to 31. 



Number 



Duration 



of larvae. 



of stage. 





Days. 



1 



4 



2 



5 



1 



6 



8 



7 



26 



8 



9 



9 



8 



10 



10 



11 



1 



12 



1 



13 



1 



14 



168 



2 8. 74 



