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fifth form of Plvjlloocera. The fate of the eggs of the radicolae is not 

 determined at the moment of oviposition, nor is that of the first larva ; 

 environment will determine whether the larva of a radicola will become 

 an apterous radicola or a winged form. Winged forms develop in 

 large numbers on American vines and also on the nodosities of European 

 vines in some places, e.g. North Italy ; but on European vines in the 

 Pisan hills, they are everywhere rare and in some seasons extremely so. 

 If, from an American vine, two rootlets are taken with first 

 larvae already adhering to them, and one is left intact, and from the 

 other, all the larvae are removed, except one, and the rootlets are then 

 carefully kept alive until the insects have become mature, the isolated 

 larva will always develop into an apterous form, whilst those remaining 

 together, mainly become winged forms. By means of similar and often 

 repeated ex]3eriments, the author has become convinced of this 

 phenomenon in the first larvae ; this has also been confirmed by 

 Borner. After hibernating, the apterous forms never become winged, 

 but that their female offspring may do so, is very probable, and is 

 thought to be the case even by Borner, but is not as yet definitely 

 proved. 



The author's latest researches regarding emergence from the soil of 

 the first larvae have shown that in infested vineyards enormous 

 numbers of Phylloxera comes to the surface of the soil, where they 

 run about like ants. These are almost all newly-hatched from the 

 egg (first larvae). The importance of this phenomenon has been largely 

 overlooked owing to the belief in the spread of Phylloxera by means of 

 the alate forms, but it is really of great consequence. It is possible 

 by careful examination, with the help of a lens, to see newly-hatched 

 insects, identical with those found on the roots, wandering about on 

 the ground near an infested vine. When the soil is very dry, watering 

 it will produce fissures from which the newly-hatched insects 

 can be seen to emerge. This emergence goes on all the time that the 

 eggs are hatching on the roots, except in spring or in prolonged drought 

 in summer. Local conditions have an important influence on the 

 time and extent of this exit from the soil and a fall of rain will increase 

 it immensely. The emergence of Phylloxera from the soil has now 

 been observed throughout the whole of Italy and occurs in any soil 

 compact enough to crack and fissure. It is now regarded as established 

 that these larvae can be carried by the wind ; infection in the direction 

 of the prevailing wind has often been observed, and there is now little 

 doubt but that small local outbreaks near a centre of infection are 

 caused by migi-ation of the larvae over the soil. They are clearly 

 attracted by light, and this possibly accounts for their presence on the 

 new rootlets thrown out by layered vines before they are to be found 

 on the main roots of the stock. The first larva may in certain cases 

 take to an aerial life on the vine and produce oft'spring capable of 

 forming galls ; adventitious roots would appear to facilitate this 

 migi-ation from the root to the leaf. 



The question of the existence of different races of Phylloxera is 

 discussed. Borner's work on the race or variety which he named 

 P. ijervastatrix in Lorraine, is reviewed. The author had intended to 

 test this variety in an experimental vineyard in Italy, but was prevented 

 from doing so by the outbreak of war. It is regarded as at least possible 



