204 THE GARDENER. [May 



place which is most suitable for them ? It cannot be sight, as their eyes are 

 merely coloured spots, and they creep as if they were blind. It cannot be hear- 

 ing, because they seek no prey but a vegetable tissue. It is probably the sense 

 of smelling ; and one may well ask if the nuclei which appear enshrined in the 

 last articulations of the antennre are not the organs of this function, the seat of 

 which has been so much disputed ? 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 ima- 

 gined 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 examples in colour and form, I incline 

 to the belief that there are no sexual differences among them. A kind of double 

 moult precedes 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. Ou the 

 morbid tuberosities of the fibrous Vine-roots, or on the off-shoots 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 ' nour- 

 ished 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, triangular-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 nympha; 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 s^\arm on the Vine-root. The details of the structure of cer- 

 tain organs — the antennee, 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 and cuniform, have a lineal areole on the 

 larger basilary half of their outer edge ; and this is enclosed in an interior ' nerv- 

 ure,' which answers, I suppose, to the radial muscle. One single oblique nervure 

 (or corneous division) is detached from this last, and reaches to the inner edge. 

 Two other lines start from the end of the wing, and, becoming narrower as they 

 proceed, advance towards the oblique nervure, but end before reaching it. These 

 are not, perhaps, nervures, but rather folds, for I have observed them absent. 



" The inferior wings, both narrower and much shorter, have a marginal nervure 

 running from the base to the middle, but it loses itself in a gentle protuberance, 

 which the wing shows in this place ; a radial nervure runs parallel to the first, 

 and disappears before it reaches the same spot. 



"The eyes, black and (relatively) very largo, are irregularly globular, with 

 marked conical nipples ; their surface is granular, but a pointed depression is 



