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 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 ' 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, 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 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 antenna?, 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 large, are irregularly globular, with marked conical nipples; their surface is granular, but a pointed depression is observed in the centre of each glandule. A round eye-shaped spot occupies the centre of the forehead.

"Among fifteen winged specimens of the Phylloxera which have come under my notice, not one has presented any sexual difference. Almost all of them laid two or three eggs, and their death (which happened soon after) may have been caused by their imprisonment in the bottles. Their eggs resembled those of the wingless Phylloxera, and though they were only two or three in number, they completely filled the abdomen of the mother. They were easily seen by placing the insect under the microscope. I do not know how long the eggs remain before they are hatched, or if they always produce the winged form of the insect. It is probable that these winged individuals serve for the transportation of this insect plague to a distance; not that their wings would serve them for a rapid flight - they are too inactive, they move them very little, and in rising from the ground their horizontal position is preserved. My observations were, however, made under very unfavourable conditions, the insect being in a state of captivity; but I suppose that even in a natural state the wind is the principal agent for the dispersion of the Phylloxera, as it is for many of the insect tribe.

In any case, the discovery of this form of the Phylloxera provided with wings, and evidently fitted for an aerial life, is sufficient to explain the hitherto embarrassing fact of the rapid spread of the Vine-plagues. As to the spread of the disease from one Vine to another, the wingless ' Pucerons' may suffice for this, as, grouped in great numbers about the lower part of unhealthy Vine-stems, they might easily attack the Vines nearest them, even if they be healthy. It may be asked in what manner these insects manage to travel from one Vine stock to another, and how they contrive to reach the fibrous roots of the newly-attacked stocks 1 Do they burrow under the soil, or do they not rather travel along the surface of the earth under cover of the darkness and coolness of night, and then, traversing the fissures in the bark, arrive in this manner at the extremities of the roots? This conjecture is a probable one, and the following experiment supports it: -

"In a case 1 yard long I placed some garden soil from Montpellier, a place entirely free from the Phylloxera. In this earth I carefully laid some pieces of Vine-cane infested with wingless 'Pucerons.' I placed a handglass over each cane, and slightly raised the glass on one side in order to allow the insect to creep out. At three centimetres' distance from the pieces of cane I put some fragments of root from a healthy Vine, on which I had made fresh wounds. In twelve hours the following results were obtained: Three ' Pucerons' had found their way from one of the Vine-canes to the nearest piece of Vine-root. Some days after, twenty young ' Pucerons' occupied the same fragment. A few insects were to be found on the other fragments. One piece of root had attracted none, but the Vine-cane nearest to it had very few insects upon it which were capable of changing their places.

"A similar experiment has been made by M. Frederic Leydier at the farm of Lancieux, near Sigondas (a part of the country already infested by the Phylloxera), and by another person near Sorgues. The results of these experiments have not been satisfactory; but this does not prove that, under other conditions, or with a greater amount of perseverance, they might not have been successful. It is fortunate that this new enemy to the Vine attacks it (in the first instance) at the base of the stem, and not underground at the fibres. As it is, a thorough dressing of the bottom of the stem with coal-tar will probably prove an insurmountable obstacle to the progress of this destructive insect; but were the case otherwise, it would be very difficult to get down deep enough to reach an enemy so well protected by the depth of the soil." N.