XXXVlll 



ECONOmC ENTOMOLOGY. 



The ravages of the Phylloxera vastatrix, and the remarkable 

 incidents connected with the life-history of this minute but for- 

 midable enemy of tlie viticulturists, have been the subject of many 

 interesting communications to the Academic des Sciences of Paris 

 and to the French Entomological Society during the past year. 



Among the innumerable remedies which have been advocated 

 and tested as a means of checking the progress of this scourge, 

 the only treatment hitherto recognised as absolutely effective is 

 the submersion of the vineyards, where practicable, during one 

 month in winter, which has been attended with perfect success. 



The principal facts ascertained in -connexion with the biology 

 of these destructive Homoptera may not be undeserving of some 

 notice, considering the vast proportions which their propagation 

 and extension have now assumed. 



The young larvae, which hybernate on the roots of the vine, 

 whether derived from the autumnal sexual races adverted to in 

 the sequel, or (as it would seem) from antecedent broods, com- 

 mence laying eggs in the early spring, their progeny producing 

 and reproducing in continuous succession by parthenogenesis, as 

 usual among the Aphides, though, unlike these, always oviparous. 

 Among these successive broods some individuals never acquire 

 wings; while others, becoming more elongate, quit the earth 

 as pupa-nymphs, furnished with rudimentary alary appendages, 

 emerging in the winged state from July to September. 



But the development of the race does not terminate here, on 

 attaining the winged condition. In an interesting memoir, ' Sur 

 le Phylloxera aile et sa progeniture,' M. Balbiani has shown that 

 these winged females (to which no males are ascribed) deposit 

 their eggs, limited from two to five, amid the down of the young 

 vine-leaves, when in captivity ; from which eggs an apterous 

 sexual race is derived, as previously described by him (in 1873) in 

 the case of the Phylloxera of the oak {P. Quercus, Fonscolombe), 

 these eggs being of two different dimensions, the larger producing 

 females and the smaller males, both sexes destitute of organs of 

 nutrition, the promuscis being reduced to a short flattened 

 tubercle, and the female having the third article of the antennee 

 pedunculated. 



