30 



THE GRAPE ROOT-WORM. 



NUMBER OF EGGS DEPOSITED BY INDIVIDUAL FEMALE BEETLES. 



The total number of eggs laid per female seems to depend upon the 

 vitality of the individual insect, and undoubtedly also upon the 

 amount of feeding by the adult. In the experiments of Table II 

 the average was 112 eggs per female, with a maximum of 263 and a 

 minimum of 14 eggs. In Table V is presented the results of the so- 

 called '' stock-jar" experiments, in which several beetles were 

 confined. 



Table V. — Egg deposition of the grape root-worm by about 57 female beetles in eight 

 stock jars, as observed in 1909 at North East, Pa.; with a summary of the length of 

 life of the beetles for each stock jar. 



Stock jars. 



I. 



II. 



III. 



IV. 



v. 



VI. 



vn. 



VIII. 



Total 

 num- 

 ber of 

 eggs. 



Number of 

 beetles. 



25. 



21. 



5. 



22. 



16. 



1 

 12. I 7. 



6. 



Date of the 

 emergence. 



July 9. 



July 10. 



July 11. 



July 12. 



July 13. 



July 16. July 19. 



July 22. 



Date of ovi- 

 position: 

 July 19... 

 July 20. 



85 















85 



105 

 33 

 44 

 21 















105 



July 21 . . . 





13 

 23 



. 











46 

 237 



91 

 100 



July 22... 

 July 23... 

 July 25... 

 July 26... 

 July 28... 

 July 29... 

 July 30... 

 July 31... 

 Aug. 1.... 

 Aug. 3 



107 

 70 

 64 

 96 

 94 

 43 

 81 

 22 



121 



38 



25 



















36 

 33 

 45 

 74 











21 

 27 

 25 







68 









218 



60 

 39 









226 



253 



104 



109 



163 



240 



42 



116 



158 



239 



282 



34 



55 



56 



75 



42 



42 



23 





41 



31 





23 









29 



13 





35 



3 



143 



26 



10 







39 









35 



36 



26 

 16 

 22 



Aug. 4 













Aug. 5.... 

 Aug. 6-... 

 Aug. 7.... 

 Aug. 8.... 

 Aug. 9 



28 

 60 

 35 

 33 







52 



14 

 28 

 38 

 29 

 34 











70 



. 66 

 36 









23 



77 

 22 



10 





152 







Aug. 11... 

 Aug. 13... 



17 





" 1 -■■----- 







38 

 12 







16 

 22 



10 

 37 



18 



Aug. 14. 









16 







Aug. 19.. 







19 

 21 



23 

 21 





Aug. 23. 















Aug. 27. 

















23 



Total ovi- 

 position 



Eggs per 

 female. . 







. 











956 

 76.5 



328 

 31.2 



138 

 55.2 



408 

 37.1 



443 

 55.3 



150 



25.0 



472 

 134.9 



246 3,141 

 82.0 55.1 



LENGTH OF LIFE OF BEETLES. 



Maximum 

 number of 

 days 



Average num- 

 ber of days.. 



Minimum 

 number of 

 days 



50 



48 



23 



47 



53 



13 



46 



53 





21.6 



20.3 



12.0 



15.9 



23.5 



5.0 



28.7 



20.2 





(i 



5 



/ 



3 



2 



' 



6 



1 





