754 
| Assembly 
the tree having its peculiar species. Thus upon the apple tree, 
we have already noticed the Apple root blight, a species of woolly 
louse producing excrescences upon the roots, and the Apple Bark 
louse. There is also the tree blight, (Eriosoma lanigera ,) which in¬ 
fests the trunk and limbs. We come now to consider this spe¬ 
cies, w'hich affects the young succulent ends of the twigs and the 
l aves, and another species which we have observed upon the 
leaves, which appears to be distinct from the Mali, though pro¬ 
bably possessing the same habits. We thus have five kinds of 
these vermin infesting our apple trees. 
In many instances it is extremely difficult to determine whether 
the lice upon our American trees and plants are identical with 
those which occur upon the same or similar vegetation in Europe, 
the descriptions given of them by the old authors being so very 
brief, and often drawn up from a superficial examination of the 
species. And I have heretofore been in much doubt whether this 
common Aphis of our apple trees was the same insect which 
similarly infests the orchards of Europe, named Aphis Mali by 
Fabricius; that species being described by him, by Kollar and 
others, as being of a green color, whereas, our insect in its winged 
state is almost invariably black, its abdomen only being green. 
But having recently been favored with specimens of the European 
insect, from my esteemed friend Dr. Signoret, of Paris, and also 
on comparing our Aphis with the description given of the Euro¬ 
pean by M. Amyot, (Annals Entom. Soc. France, 2d series, vol. 
v. page 478,) and the detailed account of the veins of its wings, 
furnished by Mr. Walker, (List of British Museum, page 985,) 
not the slightest doubt remains in my mind, but that the insects 
of the two continents are identical, and that upon this side of the 
Atlantic it has been introduced by the trees brought hither from 
Europe. 
The history of this species and its annual career is as follows : 
Early in th£ spring, sunk deep in the cracks and crevices in the 
bark of the apple trees, may be seen numbers of small, oval, black, 
shining eggs, from which these insects are produced. Scraping 
off the dead bark of old trees, and coiling the trunks of all the 
trees with whitewash at that period of the year is a practice of 
much utility, since thereby most of the eggs of this and some other 
