ECONOMIC ENTOMOLOGY. 225 



trees attacked become after a time covered with swellings, 

 checking leaf and blossom, and ultimately causing both stem and 

 twigs to decay. This state is frequently called canker, and is 

 attributed to any cause but the right one — the exhaustion brought 

 about by the persistent suckings of myriads of larv^. 



I have dwelt much longer than I intended on the Aphis ; but 

 before I pass on to other of our insect troubles, I must say a word 

 or two about the Phylloxera {P. vastatrix), which, although not 

 occurring in this country, has produced such wholesale destruc- 

 tion in the French vineyards, that its name has become known 

 throughout the claret-drinking world. The Phylloxera is a species 

 of Aphis of very small size, and somewhat different in form from 

 the species known in this country. It first appeared in France 

 about the year 1863 or 1864, and is supposed to have been 

 brought from America. It attacked first the Gard district ; then 

 rapidly spread to the south and west. Its minute size renders it 

 almost indistinguishable without a glass, and its appearance is like 

 a little yellow powder adhering to the stem of the vine. It is 

 oval in form, is furnished with two vigorous antennae, and has an 

 articulated beak more than half the length of its body. This, 

 when not in use, is folded against the lower side of the thorax, 

 where it lies between the six little legs. Its body tapers some- 

 what towards the extremity. Their changes and metamorphoses 

 are very similar to those already described. Towards the twen- 

 tieth day of their life, on their attaining the adult stage, their 

 abdomen enlarges on the sides, and four mamelons appear, and 

 immediately after the insect lays a batch of eggs. Each female 

 lays about thirty eggs in each batch, and as there are eight gene- 

 rations each year, the six months between April and November 

 suffice to produce such a horde of the voracious creatures that 

 more than half the vineyards of France have been destroyed by 

 them. And even supposing means be found to extirpate them, it 

 will require ten years for the mischief to be made good and the 

 vineyards restored. 



The evil caused to the vine by the Phylloxera is a complete 

 draining of the sap from the stems. They attack only the main 

 stems, which furnish them most abundantly with the nourishment 

 they require. In spite of the attack of these countless hving 



