RILEY NOTES ON NAT. HIST. OF GRAPE PHYLLOXERA. 2bl 



Notes on the Natural History of the Grape Phylloxera 



(Phylloxera vastatrix, Planchon) . 



By Chas. V. Riley. 



[Read Oct. iS, JS75.] 



It is well known to those who have followed the habits of 

 Phylloxera vastatrix, as these have been discovered and record- 

 ed, that one of the most important points in the life-history of 

 this insect that has hitherto remained unsettled, is the nidus which 

 the winged female chooses for the consignment of the few eggs 

 she lays. In 1S71 I ventured the supposition that these eggs were 

 deposited in the down of the leaf-buds,| but subsequent observa- 

 tion led me to believe that " the more tomentose portions of the 

 vine, such as the bud, or the base of a leaf-stem, furnish the most 

 appropriate and desirable nidi" for these winged mothers, and 

 that the eggs were also laid in minute crevices on the surface 

 of the ground, especially around the base of the vinej — all these 

 conclusions being based on observations made on the insects in 

 confinement. The question is an important one practically, as 

 the hope was entertained that, by knowing just where to look for 

 these eggs, we might be able to check the rapid spread of the 

 Phylloxera disease, since it is through them alone that the disease 

 can be started in new localities distant from infested regions. 

 Feeling, from past experience, that it was extremely difficult to 

 solve the problem in the open vineyard, and that experiments 

 with the insect confined in tubes were more or less unsatisfac- 

 tory, I built, early in September, a tight house of heavy Swiss 

 muslin, six feet high and four feet square, over a Clinton vine. 

 The house was built so as not to permit even so small an insect 

 as the winged Phylloxera to get in or out, and the vine was trim- 

 med so that but few branches and leaves remained to be exam- 

 ined. Into this enclosure I brought an abundance of infested 

 roots, and for the past five or six weeks I have been getting the 

 winged females confined where I could watch their ways. In addi- 

 tion, I prepared large, wide-mouthed glass jars, by half filling with 

 moist earth. Into the earth was then stuck a vial of water hold- 

 ing a tender grape-sprig with young leaves. The leaves were 



f Fourth Mo. Ent. Rep., p. 65. X Seventh Mo. Ent. Rep., p. 



