. The American entomologist. Entomology. 82 THE AMEEICAN ENTOMOLOGIST. two other such sijecies that infest respectively the Hickory and the Oak. Whether any or all of these species likewise infest the roots of the trees upon which they occur, remains to be ascertained. But certainly they can never emi- grate on to the Apple; for the Apple, the Elm, the Ash, the Dogwood, the Hickory, and the Oak, all belong to difi'erent botanical fiimilies; and no Plant-louse that lives upon a plant be- longing to one botanical family, can live when transfen-ed to a plant that belongs to a diffcreut botanical
. The American entomologist. Entomology. 82 THE AMEEICAN ENTOMOLOGIST. two other such sijecies that infest respectively the Hickory and the Oak. Whether any or all of these species likewise infest the roots of the trees upon which they occur, remains to be ascertained. But certainly they can never emi- grate on to the Apple; for the Apple, the Elm, the Ash, the Dogwood, the Hickory, and the Oak, all belong to difi'erent botanical fiimilies; and no Plant-louse that lives upon a plant be- longing to one botanical family, can live when transfen-ed to a plant that belongs to a diffcreut botanical family. Even when two plants belong to diflerent genera of the same botanical family, it is not often that the same Plant-louse will live indifferently upon either; and frequently the same Plant-louse will not even live indifferently upon two plants that belong to the very same botanical genus. We have a I'emarkable exam- ple of this last fact in the common Currant Plant-louse, which swarms in almost every gar- den upon the Currant, and yet was never known to shift its quarters on to the Goosebcny—a species that belongs to the very same genus (Bibes) as the Currant. Indeed so far is this from being the case, that nobody ever saw Plant-lice of any kind whatever infesting the Gooseberry. [Fig. 70.]. e y Colors—(6) dull lead color; (c) black. Fig. 70, b, shows the Apple-root Plant-louse in the larva state, with the usual wooly matter attached to its back. Fig. 70, c, shows the same iusect in the perfect or winged state, with the wooly matter all removed.* On comparing * We annex the technical description of this Plaut-lousc, Irawn up from the neent specimen. Thf. ;,t l'L.\XT-i,.,r-r. (Knosoma pyri. Fitch.) (lack, a.^ lun- a> tlu- ImkIt, joints 1 and2al- l black; .stiRm^t nale brown, 2} to 3 times as lomias wide, ntcd at botli ends, but more acutely so on the basal end, vein bonnding it behind robust and black. Discoidal as .anil stignial vein
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectentomology, bookyear1
