1869.] NEW VINE DISEASE. 205 



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 wing- 

 less Phylloxera, and though they were only two or three in number, they com- 

 pletely 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 pro- 

 bable 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 sufiicient 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 frag- 

 ments 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 in- 

 sects 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 Phyl- 

 loxera), 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 insur- 

 mountable obstacle to the progress of this destructive insect ; but were the case 

 otherwise, it would be very difi&cult to get down deep enough to reach an enemy 

 so well protected by the depth of the soil. " N. 



