SEASONAL HISTORY. 



31 



The number of female beetles for each jar has been estimated to be 

 at least half of the total number placed therein. The average number 

 of eggs per female for each separate experiment varied considerably. 

 In jar 7 there were approximately 135 eggs per female, in jar 6 only 

 25 eggs per female, or a final average for the eight jars of only 55 

 eggs per female. In considering the average egg deposition in the 

 breeding cages there were found to be about 75 eggs per female. 



THE OVIPOSITION PERIOD FOR THE SEASON OF 1909. 



The oviposition period and the number of eggs deposited for the 

 entire season is directly influenced by the time of emergence and 

 occurrence of the beetles. In Table VI is given the total egg depo- 

 sition of beetles in captivity. 



Table VI. — Records of the total egg deposition of the grape root-worm in breeding cages 

 at North East, Pa., during 1909. 



Date. 



Eggs. 



Date. 



Eggs. 



Date. 



Eggs. 



Date. 



Eggs. 



July 8 



July 13 



July 15 



July 16 



July 18 



July 19 



July 20 



July 21 



July 22 



July 23 



July 25 



Total.... 



29 



83 

 104 

 153 



43 

 155 

 149 



88 

 427 

 121 

 225 



July2G 



July 27 



July 28 



July 29 



July 30 



July 31 



Aug. 1 



Aug. 2 



Aug.3 



Aug. 4 



Aug. 5 



Total 



360 



62 



333 



379 



137 



123 



185 



28 



421 



71 



223 



Aug. 6 



Aug. 7 



Aug. 8 



Aug. 9 



Aug. 10 



Aug. 11 



Aug. 12 



Aug. 13 



Aug. 14 



Aug. 16 



Aug. 17 



Total 



291 



353 



397 



102 



19 



74 



29 



101 



152 



26 



46 



Aug. 18 



Aug. 19 



Aug. 20 



Aug. 23 



Aug. 26 



Aug. 27 



Sept. 3 



Sept. 10 



Sept. 12 



Sept. 14 



Sept. 20 



Total 



39 

 81 

 19 

 163 

 20 

 23 

 40 

 29 

 22 

 23 

 15 



474 



1,577 



2,322 



1,590 



Total number of eggs: 5,963. 



With the exception of a few early records, which were obtained 

 from beetles collected in the field June 30, these records represent 

 the total oviposition by the greater proportion of the beetles emerging 

 in breeding cages (listed in Table I), and for their entire length of 

 life. As the date of the emergence of these beetles was normal and 

 simultaneous with the occurrence of beetles under natural conditions 

 in the field, it is thought that this record of egg deposition may 

 closely approximate oviposition in vineyards. In considering the 

 relative number of eggs laid at different dates, it will be found 

 (Table VI; fig. 15) that previous to July 22, 13.5 per cent were 

 deposited; from July 22 to August 8, 71.4 per cent, and after August 

 8, 15.1 per cent. Previously it has been shown how the time of 

 emergence of the beetle varied, as a result of the development of the 

 insect under different conditions. Thus oviposition in the same 

 sections of the grape belt must differ under similar variations. The 

 extreme of such variations has been especially marked in vineyards 



