GRAPEVINE FLEA-BEETLES. 



17 



TIME AND DURATION OF THE LARVAL FEEDING PERIOD. 



The duration of the feeding period of 190 larvae varied from 15 to 

 23 days with an average of 18.59 days. The period covered by 

 records on feeding larvae extended from June 26 to July 26. Complete 

 data on time and duration of this period are given in Table XIX. 



Table XIX.- 



■Time and duration of larval feeding period of A. woodsi, North East, Pa., 

 1917. 



Date of 

 hatching. 



Date of 



entering 

 ground. 



Number 

 of larvae. 



Duration 

 of period. 



Date of 

 hatching. 



Date of 

 entering 

 ground. 



Number 

 of larvae. 



Duration 

 of period . 



June 26 

 26 

 26 

 26 

 July 2 

 2 

 3 

 3 

 3 

 3 

 3 

 3 

 4 

 4 

 4 



July 14 

 15 

 16 

 17 

 20 

 21 

 21 

 22 

 23 

 24 

 25 

 26 

 22 

 23 

 24 



5 

 6 

 1 



11 

 6 

 7 

 9 



15 

 9 

 3 

 1 

 1 

 9 



34 

 5 



Days. 

 18 

 19 

 20 

 21 

 18 

 19 

 18 

 19 

 20 

 21 

 22 

 23 

 18 

 19 

 20 



1 



July 4 

 5 

 5 

 5 

 5 

 6 

 6 

 7 

 7 

 7 

 9 

 9 

 9 



July 25 

 22 

 23 

 24 

 25 

 23 

 25 

 23 

 24 

 25 

 24 

 25 

 26 



2 

 26 

 7 

 2 

 4 

 3 

 7 

 6 

 3 

 1 

 2 

 4 

 1 



Days. 

 21 

 17 

 18 

 19 

 20 

 17 

 19 

 16 

 17 

 18 

 15 

 17 

 18 



U90 



2 18.59 



» Total. 



2 Weighted average. 



DURATION OF THE FIRST LARVAL STAGE. 



The duration of the first larval stage was from 4 to 11 days with an 

 average of 6.35 days, as shown in Table XX. The period covered 



Table XX. — First larval 

 stage of A. woodsi, North 

 East, Pa., 1916. 



Number 



Duration 



of larvae. 



of stage. 





Days. 



2 



4 



29 



5 



85 



6 



74 



7 



39 



8 



4 



9 



3 



10 



1 



11 



1237 



2 6.35 



by records on larvae of this stage extended 

 from June 26, the earliest recorded date of 

 hatching, to July 15, the latest recorded date 

 of passing the first molt. 



DURATION OF SECOND LARVAL STAGE. 



The duration of the second stage of 209 

 larvae was from 4 to 9 days with an average 

 of 6 days, as shown in Table XXL The total 

 period covered by records on larvae of this 

 stage extended from July 1 to July 21. 



DURATION OF FEEDING PERIOD OF THIRD LARVAL STAGE. 



i Total. 



2 Weighted average. 



The duration of the feeding period of the 

 third larval stage of 189 larvae varied from 4 

 to 9 days with an average of 6.62 days, as shown in Table XXII. 

 The total period covered by records of larvae in this stage is from 

 July 6 to July 26. 



