THE APPLE. 



441 



diately, the shoot having been previously so cut 

 as to remain attached to the stem only by the 

 bark. If the beetle, however, finds that the 

 pierced shoot does not fall, she turns back to 

 labour again at the same place, and cuts still 

 deeper through the branch ; and if she is not 

 able to divide it, she gets up once more to the 

 farthest extremity, by which means she gene- 

 rally succeeds in bringing the separated branch 

 to the ground. When this labour is over, she 

 feeds upon a leaf, scraping off the epidermis, 

 which serves her as food. After the beetle has 

 rested about an hour, she goes again to work ; 

 and if there be still a place for the reception of 

 a second egg on the shoot she has divided from 

 the stem, she bores a second hole with her pro- 

 boscis near the first, and, laying another egg, 

 pushes it into its proper place. When the twi- 

 light comes on, she reposes under a leaf for the 

 night. Next morning, as soon as the sun is up, 

 the female beetle again begins her day's work, 

 and often continues this employment until after 

 the end of June, so as, by this means, to leave a 

 numerous offspring behind her. The egg in the 

 shoot is hatched in the course of eight days, and 

 a white grub, with a black head, then makes its 

 appearance. It feeds on the pith of the shoot, 

 and if the shoot falls off, it arrives at its full size 

 in four weeks. It then leaves its dwelling, and 

 buries itself some inches deep in the earth. It 

 there prepares itself a roomy chamber, in which 

 it remains till spring, when it again appears as a 

 steel-blue coloured weevil." The whole economy 

 of this insect is extraordinary ; and besides it 

 there are many others of very similar habits, 

 many of them laying their eggs in the pith of the 

 petiole or foot-stalk of the leaf ; and instead of 

 cutting off the leaf at once, they perforate the 

 foot-stalk at both sides, and deposit their eggs in 

 the orifices, causing an interruption to the flow 

 of the sap which leads to the withering up and 

 falling off of the leaf, from which the grub escapes, 

 and enters the earth, and by spring is transformed 

 into a perfect beetle. Both the shoots in the 

 former case, and the leaves in the latter, must 

 fall to the ground, that new weevils may be pro- 

 duced, because their transformation takes place 

 in the earth, and not in the branch or leaf. A 

 knowledge, therefore, of the habits of insects, 

 closely studied, points out, in most cases, the 

 means for their reduction. In the present case, 

 the bitten-off shoots and the fallen leaves should 

 be carefully collected as soon as they have fallen, 

 and consigned to the nearest fire, because in 

 them are enclosed the eggs of the insects, which, 

 if left to lie on the ground, would only afford 

 means for the grubs reaching the earth, which 

 is their natural and necessary winter abode. 



Several species of the genus Yponomeuta are 

 exceedingly destructive to garden productions. 

 Y. padella of most authors, changed by Zeller to 

 Y. variabilis, feeds on the sloe and white thorn, 

 often completely denuding them of their foliage. 

 It also attacks the bird- cherry (Prunus padus), 

 although to a much less injurious extent. Y. 

 cognatella of some, Y. euonymi of Zeller, feeds on 

 the leaves of Euonymus Europeeus. Y. padi of 

 Zeller is exceedingly destructive to Prunus padus 

 —chiefly, however, attacking old trees. Y. mali- 



vorella (of Stainton), fig. 188, is the species of 

 this genus most destructive to the apple tree. 



Fig. 188. 



YPONOMEUTA MALI VOR ELLA AND CATEKFILLAKS. 



It differs from Y. padella in the pure bright 

 white colour of its upper wings, marked with 

 numerous small black dots : the cocoon is also 

 different from that of Y. padella, being also 

 white, but so opaque that it is impossible to see 

 the enclosed chrysalis. 



The caterpillars of Y. malivorella commit sad 

 devastation in most seasons upon the leaves of 

 apple trees, devouring them as fast as they deve- 

 lop themselves. Nor is it by feeding on the 

 young foliage alone that they destroy it; they 

 also spin a strong white shining web, with which, 

 they so completely cover the young shoots, and 

 even oftentimes the older branches, as to pre- 

 vent the free development of the leaves, while 

 the web, hanging in festoons from branch to 

 branch, offers a ready means of communication 

 to every part of the tree. 



Very great confusion appears to exist amongst 

 entomologists regarding this insect ; most of 

 those we have consulted appear to confound Y. 

 malivorella with Y. padella. Kollar, Hubner, 

 and M. Guerin Meneville, who has been em- 

 ployed by the French government in investigat- 

 ing the insects injurious to cultivators, have all 

 fallen into this mistake ; while Treitsche seems 

 to confound it with Y. cognatella, which is also 

 a distinct species. We have been unable to meet 

 with any very satisfactory description of Y. mali- 

 vorella, and therefore beg to refer the interested 

 reader to Mr Lewis's history of its earlier stages, 

 in the " Transactions of the Entomological So- 

 ciety," vol. i., and to Mr Stainton's " Systematic 

 Catalogue of British Tincidae and Pterophoridse." 



