THE VINE-PEST IN ROSSENDALE. 227 
accounts for the vastness of their number, when in other respects 
the conditions are favourable to their growth and development. 
The individuals found in spring and early summer, and which may 
be either winged or apterous, (not winged) are all of one sex, and 
give birth to others like themselves. During the whole of this 
time only these undeveloped females are met with, and generation 
follows generation, without the appearance of a single male. As 
many as from seven to ten, or even more broods, may thus be 
produced in a single season; so that from a single aphis it has 
been calculated that ten thousand million millions (Dr. Carpenter) 
may be produced in that.period. In the autumn males and true 
females are produced, the former winged and the latter apterous ; 
these perform the generative process, the females lay eggs, which, 
when hatched in the succeeding spring, give origin to a new brood, 
which repeats the curious life history of their predecessors. To 
those who have not studied Natural History the above account of 
their method of reproduction will: probably appear incredible, but 
it is too well authenticated to be disputed; besides which, some- 
thing similar takes place in other animals, notably in Entomos- 
traca (waterfleas), a small animal allied to shrimps and prawns, in 
rotifera, minute wheel-animalcula, and also in the hydra, an 
interesting animal found plentifully in our ponds and ditches. The 
phylloxera, whose history and development we have traced above, 
during the time that males and the true females are found, live 
upon the leaves of the vine ; as a consequence they curl up, their 
surface becomes covered with small brown tubercules, and frequently 
their attachment to the stem becomes so weak from lack of nourish- 
ment that they fall off. Afterwards the females move down to the 
roots, where they lay their eggs in the interstices of the bark, and 
on examination they may be found there in great numbers, often sur- 
rounded by a zone of eggs, which, I may say, are about half the 
length of the insect, and of the same beautiful hue. Many years 
ago this insect caused immense havoc among the vines in France, 
Italy, and Spain, but especially in France ; whole districts were 
infested with it, and the grape crop was a complete failure. Hun- 
dreds of thousands of pounds damage was done in a single season, 
so that the revenue was seriously affected, and the Government 
took active measures to eradicate the obnoxious insect. Large 
rewards were offered for effective means of doing so ; many plans 
were sent in, which we need not enumerate ; suffice it to say that 
completely rooting up the plants in the infected districts and burn- 
ing them seemed to be the only way of arresting the scourge. Some 
parts of our Australian colonies have been similarly affected, and 
the Government there, I believe, as a protection to non-infected 
districts, are insisting upon a like mode of procedure, indemnifying 
the cultivators for their losses. It has been known in England for 
