THE GRAPE VINE. 121 



putedi Among these non- adult insects, attached by their 

 suckers to the vine -root, are seen, here and there, some of 

 middle size. Their colour is a deeper orange, the abdomen 

 shorter and more squarely formed. These individuals are more 

 sedentary than the others. I have sometimes imagined they 

 might be wingless (apterous) males of the species ; but as nothing 

 has happened to confirm this very problematical hypothesis, and 

 as I have seen undoubted females much resembling these ex- 

 amples in colour and form, I incline to the belief that there are 

 no sexual difi^erences among them. A kind of double moult pre- 

 cedes the adult state. The first takes place shortly after birth, 

 the second after laying-time. Some uncertainty, however, hangs 

 over the number of these changes, as the cast-off skins are often 

 found mixed up with groups of pucerons of different ages, and 

 it is difficult to distinguish them. On the morbid tuberosities 

 of the fibrous vine-roots, or on the offshoots of the roots, the 

 pucerons (perhaps better nourished) seem to pass more quickly 

 through the different phases I have described ; but excepting 

 that their colour is paler, they present no marked difference. 



" The winged form of the Phylloxera might easily be taken for 

 a separate species. The rare specimens which I have seen have 

 all come from the pucerons nourished on the newly - attacked 

 vine-radicles. In their infant (or it might be called their larva) 

 state they resemble those which I have suggested may be males, 

 but the buckler soon becomes more strongly marked than in these 

 last ; and a kind of band seems distinctly to define the separation 

 between this and the abdomen. The sheaths of the wings, trian- 

 gular-shaped and of a greyish colour, appear on both sides of the 

 buckler. It is easy to predict the advent of a winged insect from 

 this chrysalis. When one of these nymphse is seen to quit its 

 place and to crawl over the root, or up the side of the bottle where 

 it may have been put, its transformation is near. Soon, instead 

 of a sort of pupa, a beautiful little fly appears, whose two pairs of 

 wings, crossed horizontally, are much larger than its body. 



" It is impossible to doubt the identity of this insect with the 

 puceron which formed one of the swarm on the vine-root. The 

 details of the structure of certain organs — the antennse, claws, 

 tarsi, and suckers — establish their identity. 



" The horizontal position of the wings completely distinguishes 

 the Phylloxera from the true aphis, whose wings are always more 

 or less inclined upwards. The two larger wings, obliquely oboval 



