THE GBAPE-BEBEY MOTH. 



33 



Table IV. — Length of incubation of first brood of eggs of the grape-berry moth at North 



East, Pa., in 1909. 



No. of obser- 

 vation. 



Date- 



Days of 

 incu- 

 bation. 



No. of obser- 

 vation. 



Date- 



Days of 

 incu- 

 bation. 



Laid. 



Hatched. 



Laid. 



Hatched. 



1 



June 25 

 June 26 

 June 27 

 June 28 

 do... 



June 29 

 July 1 

 July 2 

 July 4 

 July 5 

 ...do.... 

 July 6 

 July 7 

 July 8 

 July 9 

 July 10 



4 

 5 

 5 

 6 

 7 

 6 

 7 

 7 

 7 

 7 

 8 



12 



July 3 



...do 



July 5 

 July 6 

 July 7 

 July 8 

 July 9 

 July 10 

 July 12 

 ...do. 



July 10 

 July 11 



...do 



July 12 



...do 



July 13 



...do 



July 16 

 July 17 

 July 18 



7 

 8 

 6 

 ' 6 

 5 

 5 

 4 

 6 

 5 

 6 



2 



13 



14 



3.. 



4 



15.. 



5 



16.... 



6 



June 29 

 .do 



17.. 



7 



18 



8 



June 30 

 July 1 

 July 2 

 ..do 



19.. 



9 



20 



10 



11 



21..... 











Days of incubation: 



Average 6 



Maximum 8 



Minimum 4 



Length oj jeeding period oj Jlrst-brood larvse. — The records for the 

 length of the feeding period of the first-brood larvse are given in 

 Table XI (p. 37), which shows a range from 19 to 33 days and an 

 average of 23.2 days. The small number of observations made 

 was due to the difficulty of securing the deposition of a larger num- 

 ber of eggs from the moths in captivity. 



Length oj pupal stage oj first orood. — Table V gives the time of leav- 

 ing the fruit of 285 first-brood larvse and the date of emergence of the 

 moths. The average time for making the cocoon was approximately 

 2 days. The minimum time covered from leaving of fruit to emer- 

 gence of moths was 10 days, the average 15.2 days, and the maxi- 

 mum 25 days. Therefore, deducting 2 days spent by the larva in 

 making the cocoon the minimum pupal period was 8 days, the average 

 13.2 days, and the maximum 23 days. 

 60141°— Bull. 116, pt 2—12 4 



