60 
FIRST ANNUAL REPORT OF THE 
Cherry-tree, or the Cherry-tree Plant-louse on to a Plum-tree, or the Plum-tree Plant- 
louse on to a Peach-tree, and it will before many days die of starvation. Yet these 
trees all belong to the same botanical Family. Dr. Fitch has remarked that the im¬ 
ported species of Plant-louse, that inhabits the tame Cherry-tree, cannot live even upon 
any of our wild Cherry-trees, and that even the wild Black Cherry ( Cerasus serotina ) and 
the Choke-cherry ( Cerasus virginiana ), closely related as they are, are inhabited by 
distinct species. (W. Y. Rep. I. p. 131.) Again: the Currant and the Gooseberry 
belong to the same genus. The Currant is notoriously infested by a Plant-louse (Aphis 
ribis, Linmeus) which has been imported along with that shrub from Europe. Yet, 
although these two plants are often grown in gardens side by side, nobody ever saw any 
plant-lice of any kind on the Gooseberry, much less the true Currant Plant-louse. Yet, if 
the same species of Plant-louse can feed almost indiscriminately upon any kind of plant, 
why does not the Currant Plant-louse emigrate on to the Gooseberry ? I have myself 
observed that different species of Plant-lice (Aphis) inhabit different species of Oak ; 
for example, the Handsome Plant-louse (Aphis Mia , Walsh) is peculiar to the Black Oak 
(Quercus tinctoria ), where, since I described the species, I have found it in abundance in 
company with its larva ; and an undescribed species of the same genus, with remark¬ 
ably stout branch-veins to its front wings, is peculiar to the Swamp White Oak, (Quercus 
prinus , var. discolor.) 
As regards the Root Plant-lice, we know but very little of the species found in this 
country, because, like other underground insects, they are hidden from our observation 
in the bowels of the earth. Indeed, besides the species now under discussion, the only 
other described North American species are two, which I myself was the first to discover 
and describe in the winged state, and which I found to be carried home by certain Ants 
to the nests inhabited by the young larvae of these Ants, for the sake of the sweet, 
woolly matter secreted by them, and thence carried back again to the roots on which 
they fed—just as a dairyman drives his cows up to be milked and then drives them 
back again to pasture.* Both these species are quite distinct from the Apple-root 
Plant-louse; and I am acquainted with several others, but only in the wingless state, 
which are also quite distinct from that insect. As to the true “ Woolly Plant- 
louse ” of the Apple-tree, the European entomologist Blot says, that “ it can only live 
upon the Apple-tree, and if transplanted upon any other tree, it very soon perishes.” 
(Amyot and Serv. Hemipt. p. 610.) 
What is probably the wingless female form of this Apple-root Plant-louse measures, when fully 
grown, about 0.07 inch long, at which time, after removing the white down, it is of a dull lead color. 
The antennae are indistinctly 6-jointed, with the length of the joints proportioned nearly as 2, 2, 4, 2, 2 
3, the last joint including a short terminal seta (unguiculus). The beak extends to the base of the mid¬ 
dle legs. 
The color of the young larva is dull yellowish, as described by Fitch. The antennae are indistinctly 
5-jointed, the joints nearly equal, joint 3 a little the longest, and 5 with a minute terminal seta. When 
the larva is very young indeed, the beak is longer than the body, and projects behind so as to resemble 
at first sight, the honey-tube of the genus Aphis and its allies. When older, the beak is about two-thirds, 
as long as the body. 
I have not yet obtained the winged form of the female ; but a full description of it is given by Fitch. 
It occurred in New York on October 29th. (N. Y. Rep. I. pp. 9 —10.) 
After a group of these lice has been stationed on a root in the open air for two or three 
*See Proc. Ent. Soc. Phil. I. pp. 307—8; and Trans. Ill. State Agr. Soc. V. pp. 493—4. 
