( Hii ) 



3. The pseudogyna migrans, issuing from the galls and 



descending to the roots, in July. 



4. The pseudogyna gemmans, feeding on the large roots, in 



August. 



5. The pseudogyna pupifera, feeding on the small roots where 



they form blebs or swellings. These insects pass into 

 nymphs, then issue from the soil and on the surface 

 develop wings, in September. They fly to the vines, 

 to deposit their eggs (pseudova, or, as Lichtenstein would 

 say, pupas) under the leaves or in the fissures of the 

 bark. 



6. From these the sexed forms appear. After union, the 



female goes under the bark, where she lays a single 

 egg, and dies in October. 



Each of the four pseudogynous or agamous stages is separated 

 from the following one by an egg-like quiescent state, so that the 

 pseudogynes, which in other Aphides are viviparous, are in the 

 Phylloxerida oviparous. 



The first stages of P. vastatrix are all wingless, the so-called 

 pupifer only being winged. This last form alone produces the 

 males and females, which are exceedingly small and absolutely 

 mouthless, living only for reproduction, the female laying her 

 egg about the fourth day after she is hatched. The foundress 

 punctures the leaves in such a manner that the swelling masses 

 close over and finally entomb her ; the leaves become studded 

 with gall-like excrescences, each foundress forming a single gall, 

 within which she lays hundreds or even thousands of eggs : after 

 developing on the leaf and escaping from the gall, the young 

 Phylloxera descends into the ground and commences its sub- 

 terranean existence, attacking the roots of the vines and causing 

 swellings or tubercles thereon ; so numerous are the creatures 

 that the roots when turned up often appear dusted with yellow 

 grains. 



The first notice of the Vine-Aphis is by Asa Fitch in 1855 

 (the grape-leaf louse, Pemphigus vitifolii) in his ' First Keport 

 on the Noxious, Beneficial and other Insects of the State of New 

 York': it is not indigenous to Britain, but in 1863 it had been 

 introduced into England, and was named by Westwood Peritymbia 

 vitisana; shortly afterwards it invaded France, and has spread 



i 



