THE GRAPE VINE. 1 23 



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 Phyl- 

 loxera, 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 pre- 

 served. 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 princi- 

 pal 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 this vine-plague. As to the spread of the disease 

 from one vine to another, the wingless pucerons may sufiice for 

 this, as, grouped in great numbers about the lower part of imhealthy 

 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 ? 

 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 Montpel- 

 lier, a place entirely free from the Phylloxera, In this earth I 



