ACTING STATE ENTOMOLOGIST. 
55 
tured female scale of every species of this genus known to me. I have never actually 
bred the males from this type of scale, neither, as it seems, did Harris ; but I have now 
little doubt that Harris’s opinion is the correct one, and that I was entirely mistaken 
when I formerly imagined, that these empty scales were the cast skins of the immature 
females. ( Practical Entomologist , II. p. 32.) 
As to the geographical distribution of Harris’s Bark-louse, Harris found it, but appar¬ 
ently only in small numbers, in Massachusetts. Dr. Houghton is pestered with it 
awfully in Pennsylvania, and Dr. A. Chandler, Montgomery Co., Maryland, must also 
have it in abundance ; for he says that his pear-trees “have stopped growing and are 
covered with white lice, which, when mashed with the point of a knife, discharge a red 
fluid.” {NewYork Sem. Tribune , March 26, 1867.) I have myself seen specimens near 
Cobden, South Illinois, some of which occurred on the European Mountain Ash ( Sorbus 
•aucuparict,) a tree which Dr. Asa Gray places in the same genus as the Pear and the 
Apple. I have likewise received specimens from the orchard of W. C. Flagg, near 
Alton, in South Illinois. And it must occur in St. Clair Co., also, in South Illinois ; for 
at a Meeting of the Alton Horticultural Society, May 2, 1867, President Pearson 
reported that he had found “upon trees purchased in St. Clair County, Bark-lice or 
Scale-insects containing eggs, which when broken gave out a red-colored juice.” Dr. 
Mygatt mentions it, under the appellation of the “ white variety ” of the Oyster-shell 
species, as common in Kane and McHenry Cos. in North Illinois, and I have long found 
it pretty abundantly in Rock Island County, both on apple-trees and on the crab. 
Lastly Bark-lice, which, as it would seem, can only belong to this species, are reported 
from Hartville, Wright Co., Missouri, which is nearly in the latitude of the extreme 
southern point of Illinois, as “ utterly destroying the best apple-orchards in that county, 
starting on the trunks of the trees, spreading rapidly on the branches, and then on the 
apples — killing large trees in two years.” ( Rural World, Oct. 15, 1866.) I heard no 
complaints of this insect being at present at all troublesome near Cobden, South 
Illinois ; but at some future day it may likely enough make an irruption upon the pear 
orchards of Southern Illinois in full force. 
I observe that on all my apple-trees, which were infested a year or two ago by Harris’s 
Bark-louse, this native species is being gradually supplanted by the improved and 
highly-developed species from the other side of the Atlantic ; just as the White Man is 
supplanting the Red Man in America, or as in New Zealand the European House-fly 
{Musca domestica , Linmeus,) and the Brown Norway Rat ( Mus decumanus , Linnaeus), are 
driving out the Native Fly and the Native Rat. (See Spencer’s Principles of Biology , I, 
p. 389.) It is preyed on by the same Mites as the other kind, and, being so closely 
allied to it, must be attacked on the same principles and with the same weapons. 
INSECTS INFESTING THE APPLE. —On the Root. 
CHAPTER X. — The Apple-boot Plant-louse, {Pemphigus pyri, Fitch,) commonly 
but incorrectly called in Illinois “ The Woolly Aphis.” 
This insect has been very generally confounded with the true “ Woolly Plant-louse 
or “ Woolly Aphis ” ( Eriosoma lanigera , Hausmann), which, so tar as is known at present, 
occurs only on the Atlantic seabord, though it may perhaps eventually work its way 
Westward into the Northern parts of the Valley of the Mississippi. It is very true that 
both insects are “ woolly,” inasmuch as they both secrete a woolly or cottony substance 
