THE GRAPE PHYLLOXERA IN CALIFORNIA. 



87 



location of the sexed eggs. Taking the sum of these discussions, 

 it appears that they are placed on the underside of the leaves and 

 more abundantly in the bark, generally between the year-old layer 

 and that of the current year, and are fastened to the inner side of 

 the former. Occasionally eggs are found at the base of canes where 

 the new wood joins the old, and rarely on the vine supports (stakes). 

 They are laid on both viniferse and resistant vines, but preferably on 

 the latter. 



Observations were conducted in small cages, and in a few instances 

 on living vines in pots. In the latter instances eggs were found laid 

 on both the foliage and bark. Many different kinds of cages were 

 used and experiments with different degrees of light, moisture, and 

 temperature were conducted. Vine leaves and pieces of bark were 

 inclosed in the cages. As a rule, the migrants, though primarily 

 attracted to light, deposited their eggs in semidarkness. They laid 

 them on the leaves and more rarely on pieces of bark offered, but 

 often also on the sides, lid, and floor of the cages and in cracks. In 

 1911 the observations tabulated in Table XXVII occurred. 



Table XXVII.- 



-Sexual production of the grape phylloxera, Walnut Creek, 

 Calif., 1911. 



Number 

 of mi- 

 grants. 



45 

 103 



Date and location of migrants. 



Aug. 4-6: Riparia vine in pot. . . 

 Aug. 7-8: Vinifera vine in pot . . 

 Aug. 10-12: Riparia vine in pot. 



Aug. 13, 14: Vinifera vine in pot. 



Aug. 15: Riparia vine in pot 



Aug. 16: Riparia vine in pot 



Aug. 17: Glass tube in drawer 



Aug. 18, 19: Riparia leaves in petri dish 



Aug. 19: Leaves in petri dish 



Aug. 23: Leaves in petri dish 



Aug. 24: Riparia leaves in laboratory. 



Aug. 25, 26: Riparia leaves in petri dish. 



Aug. 25, 28, 29: Riparia leaves in petri dish. 

 Sept. 2-17: Vinifera vine in pot 



Sept. 19-23: Riparia vine in pot. 

 Sept. 25-29: Riparia vine in pot. 



Number 

 of sexual 

 eggs de- 

 posited. 1 



Date of 

 deposi- 

 tion. 



Aug. 9 



Aug. 16 



Aug. 15 

 Aug. 20 



...do 



...do 



Aug. 21 

 Aug. 22 

 Aug. 23 

 Aug. 19 

 Aug. 23 

 Aug. 25 

 Aug. 26 

 Aug. 27 

 Aug. 28 

 Aug. 29 

 Aug. 27 

 Aug. 28 

 Aug. 30 

 Sept. 3 

 Sept. 25 



Sept. 29 



Date of 

 maturing 

 of sexes. 



Aug. 26 

 Aug. 28 

 Aug. 30 



Sept. 6 



Aug. 30 

 Sept. 2 



Oct. 4 

 Oct. 5 

 Oct. 6 



Number 

 of sexes 

 ma- 

 tured. '- 



1 Thirteen female and three male eggs. 



2 All maturing sexuals were females. 



Table XXVIII. — Summary of Table XXVII. 



Number of migrants '_. 



Number of sexual eggs depositecL 

 Number of sexual eggs hatched- _ 



734 



171 



13 



