356 



THE AMERICAN 



his house in tlie winter ; but, Proteus-like, they 

 change their appearance in shedding their skins, 

 and at the present time (Nov. Cth) have all be- 

 come tubercled, as represented at Figure 219, g. 



No doubt the insect passes the winter on the 

 roots in this tubercled state, but whether in the 

 spring these tubercled individuals produce 

 winged males and females, which rise in the air, 

 pair, and by depositing eggs give birth to the 

 apterous females which found the gall-producing 

 colonies, or whether, as spring opens, they lay 

 eggs on the roots, and the young hatching from 

 these eggs crawl up on to the leaves and found 

 those gall-producing colonies, are questions yet 

 to be settled in the life-history of our G rape leaf- 

 louse. The former hypothesis is, however, by 

 far the most probable, for analogy would lead 

 us to infer that winged males and females must 

 be developed' at some time during its annual 

 course, and winged males arc so rare in the galls 

 that we have never been able to find them, 

 though we have opened thousands upon thou- 

 sands of the galls during the summer and Ml 

 months. Dr. Shinier, indeed, is the only fortu- 

 nate individual who has found the wiuged in- 

 sect in the galls, and, as he himself tells us, he 

 only succeeded in finding four specimens iu the 

 fall of the year, after cutting open ten thousand 

 galls; and he has really given us no proof that 

 his winged specimens were really males, and not 

 females. Let us hope, however, that by point- 

 ing out tlie gaps in the biological history of this 

 insect, attention will be di-awn to them, so that 

 they may be the more readily filled. 



These discoveries lead us to some most impor- 

 tant practical considerations. It now becomes 

 evident that this insect can be transported from 

 one place to another on the roots, either upon 

 transplanted vines or in earth containing fibrous 

 roots. Doubtless it was by some such mode as 

 this that the insect was introduced into France 

 from this country. It may be iu tliis manner like- 

 wise that it has in part spread from one portion 

 of our country to another, though as it is found 

 indigenously on the wild Frost Grape, the 

 greater probabilities are that it exists wherever 

 this wild grape is found, and has gradually 

 spread from it on to the cultivated varieties. 

 These probabilities are strengthened by the fact 

 that new grape wood is always rooted in the 

 spring, when the lice, according to our views, 

 are leaving the roots. But the important fact 

 remains, that the insect winters on the roots, and 

 that to exterminate it from a vineyard we have 

 but to root up and destroy, late in the fall, such 

 vines as were affected with the gaUs. From the 

 poor success that has attended the experiments 



made abroad to destroy the lice on the roots, and 

 from the fact that it is so difficult to reach them, 

 we have little hope that any other remedy wiU 

 be found than that of extermination by the 

 means indicated, or by plucking and destroying 

 the gall-infested leaves as fast as they appear in 

 the spring. 



Another very important practical lesson may 

 be derived from the facts we have mentioned, 

 namely, that no variety of the Frost Grape ( V. 

 cordifolia) should be cultivated and encouraged 

 where those of the Fox Grape ( V. labrusca) or 

 of the Summer Grape ( V. cestivalis) are known 

 to be as good. Some of our best gi-ape-growers, 

 especially in the Mississippi Valley, already dis- 

 card the Clinton and its nearest relatives as 

 worthless, and, considering its liability to tliis 

 disease, we heartily commend their conduct. 



There is some dilTerence of opinion among 

 botanists and experienced grape-growers as to 

 the number of indigenous species of the grape- 

 vine, and as to the true character of some of the 

 cultivated varieties, fome botamsts are inclined 

 to the opinion that we have but two, or even but 

 one, species; and certain it is that the fertile 

 character of the hybi-ids would lead to such an 

 opinion; but it is more generally accepted that 

 we have four distinct species ( V. labrusca, CBsti- 

 valis, cordifolia and vuljnna) and this view is 

 held by most western men.* 



As already stated, our Grape leaf-louse is now 

 principally confined to varieties of the Frost 

 Grape ;t but as it has been found iu limited 

 numbers on lona and Concord, which are con- 

 sidered as varieties of the Northern Fox, and on 

 the Delaware, which is considered either as a 

 Summer Grape or as a hybrid between the Sum- 

 mer and the Northern Fox, we fear it may yet 

 spread and become injurious to these species. 

 Moreover, now that we know that our insect is 

 identical with that of Europe, there is also great 

 danger that it will attack all hybrids with the 

 European Vinifera, some of which, as the 

 " Goethe," now promise weU. Thus the reasons 

 for discarding the Clinton and other Frost grapes 

 become multiplied, for their cultivation may en- 

 danger the whole grape-growing interest of the 

 country. On entomological grounds, we say 

 emphatically to western men, do not plant any 

 more Clintons, and get rid of those you now 

 have as quickly as possible. 



t Though Gray considei's the Clinton a variety of the JEsH- 

 valis^ It la more generally considered as belonging to Cordi- 

 folia, which its great liability to the gall-louse would 

 indicate. 



