THE GRAPE PHYLLOXERA, 13 



oviposition. Two or three days after this operation the motlier dies ; 

 but the males live as long again. 



This solitary egg^ which Balbiani calls the winter-egg, soon takes 

 on a dark color, which indicates its fecundity and distinguishes it 

 from parthenogenetic eggs of both the winged and wingless females. 

 It is surmised that this egg passes the winter to give birth in spring 

 to the form destined to recommence the cycle of development belong- 

 ing to the species. 



These discoveries are truly remarkable, and appear to me all the 

 more so since Balbiani^ likewise found that the individuals which 

 never become winged attain maturity without laying eggs on the 

 leaves on which they were born, but crawl on to the branches and in 

 the interstices of the old scales at the base of the new year's growth. 

 There they lay a number of eggs, which are absolutely like those de- 

 posited by the winged females^ and^ like them^ produce the sexual indi- 

 viduals^ i. e., both males and females. Now, this does not correspond 

 with what I have seen myself of the species, or with what has been de- 

 scribed by others ; for the apterous individuals of quercus surround 

 themselves with eggs on the leaves where they are born. 



M. Max-Cornu has already announced having found a sexual indi- 

 vidual, without mouth-parts, of the Grape Phylloxera ; and it is quite 

 likely, now that Balbiani has paved the way, that we shall next year 

 have its natural history complete. But whether the Grape Phylloxera 

 produces this fecundated and solitary egg or not, such an egg is neither 

 essential to its winter life, nor to that of an American species [Phyl- 

 loxera Riley i Lichtenstein), which will be described farther on, and 

 which is, in every respect, very closely allied to the European quercus. 



While, therefore, there is much yet to learn in the life-history of 

 our Grape Phylloxera, the facts which I have already unequivocally 

 stated, as well as those which I shall now proceed to give, remain in- 

 disputable, and do not seem fully to accord with Balbiani's discoveries. 



As fall advances the winged individuals become more and more 

 scarce, and as winter sets in only eggs, newly-hatched larvae, and a few 

 apterous egg-bearing mothers, are seen. These last die and disappear 

 during the winter, which is mostly passed in the larva state, with here 

 and there a few eggs. The larvjs thus hibernating (Fig 4, b) become 

 dingy, with the body and limbs more shagreened and the claws and 

 digituli less perfect than when first hatched ; and, of thousands exam- 

 ined, all bear the same appearance and all are furnished with strong- 

 suckers. As soon as the ground thaws and the sap starts in the spring, 

 these young lice work off their winter coat, and, growing apace, com- 

 mence to deposit eggs. All, without exception, so far as I have seen,^ 

 become mothers and assume the degraded form [a) already described. 



* Audore Dr. Fr. Cazalis, as reported in the Messager du Midi, November 16, 1873. 

 2 I have examined thousands in the vineyard in early spring, and other thousands 

 reared artificially in a warm room in winter. 



