26 



THE GRAPE ROOT-WORM. 



of this first feeding. The voracity with which newly emerged bee- 

 tles feed is indicated in the poison -spray experiments described on 

 page 65. Fifty per cent of newly emerged beetles were killed the 

 first day, against 10 per cent of older beetles, both sets being sub- 

 jected to identical conditions. 



The feeding of the beetle is confined mainly to the upper surface 

 of the leaves; the parenchymals devoured, leavilig characteristic 

 chainlike feeding marks, as shown in Plate 11. With individual bee- 

 tles the length of time of feeding previous to egg deposition varies 

 considerably. In Tables II and III is given the record of 16 

 individual females, showing a feeding period before oviposition vary- 

 ing from 9 to 24 days, with an average of 15.9 days. 



Table II. — Oviposition, feeding, and length of life of individual male and female beetles 

 of Fidia viticida in captivity during the summer of 1909 at North East, Pa. 





1. 



2. 



3. 



4. 



5. 



6 







Date of emergence of beetles 



June 30 



June 30 



June 30 



June 30 



July 2 



July 2 





Mated 



July 8 

 July 22 



31 

 July 25 



31 

 July 26 



40 

 July 28 



25 



July 8 



July 21 



17 



July 26 



6 



July 8-9 

 July 15 



26 

 July 16 



19 

 July 27 



14 

 July 29 



61 



July 14 



July 21 



15 



July 13 

 July 15 



17 

 July 28 



14 

 Aug. 3 



Aug. 8 





First oviposition 



July 19 

 35 



Eggs 





July 26 

 36 



Eggs 









July 29 

 31 



Eegs 













July 31 

 14 



Eggs 







Fifth oviposition 





















Sixth oviposition 



























Seventh oviposition 















Eggs 















Eighth oviposition 















Eggs 





























Eggs 





























Death of male 



Aug. 8 

 Aug. 1 



Aug. 26 

 Aug. 2 



Aug. 19 

 Aug. 3 



July 23 

 July 23 



Aug. 25 

 Aug. 9 





Death of female 



Aug. 3i 



Days of feeding before oviposition 



22.0 

 4.0 



25.0 

 31.8 

 40.0 

 127.0 

 39.0 

 31.0 



21.0 

 2.0 



6.0 

 11.5 

 17.0 

 23.0 

 57.0 

 32.0 



15.0 

 4.0 



14.0 

 30.0 

 61.0 

 120.0 

 50.0 

 33.0 



21.0 

 1.0 



15.0 

 15.0 

 15.0 

 15.0 

 23.0 

 23.0 



13.0 

 4.0 



4.0 

 10.0 

 17.0 

 40.0 

 54.0 

 38.0 



17.0 





6.0 



Eggs per cluster: 



14.0 



Average 



25.5 



Maximum 



36.0 



Total number of eggs 



153.0 







Length of life of female 



60.0 







