STATE HORTICULTURAL SOCIETY. 165 



all to remember and observe, that while discussing scientific subjects we can never gain 

 anything worth having by departing from the paths of science and stooping to person- 

 alities and misrepresentation, and were it not for the sake of the cause I would vindi- 

 cate, I would not think their strictures worthy of notice. 



Yovfood, this oyster shell bark louse, in the main, adopts the cultivated apple tree, 

 sucking the juices from the bark by means of a proboscis adapted to its purposes; 

 neither is it confined to the apple, but as has often been proven, has been found on the 

 curi'ant, plum, pear, moiuitain ash, etc, and was originally described from the elm, 

 all of which have frequently been made public by various authors. That is we have it 

 in the genus Rihes, order, Grossulacece ; on the genus Prunus and sub-genera Malus and 

 Sorhus of the genus Pyrus, order, Rosacem, and on the genus Vtrmis, order, Urticacea: 

 That is, in plain English, the " oyster shell bark louse ' ' feeds on members of the rose 

 family, currant family, and nettle family. These families are as widely separated, 

 botanieally, as in the example already given of lecanium, and is another reason why 

 we cannot name even bark lice on account of the food plants on which they are found, 

 being of a diflerent genus or of a different family. All of this I endeavored to make plain 

 in a paper offered to the Northern Illinois Horticultural Society at Aurora, Feb. 10, 

 1869, entitled " The Apple Baric Louse in 1868," misprinted 1866, which was pub- 

 lished in the Transactions of the Illinois State Horticultural Society for 1868, page 227. 



That paper was written 1,000 miles away from home, when I was closely pressed 

 with other duties. I neglected to notice the fact that the bark louse was found on the 

 currant, intending to do so in the proof sheets, giving an authority, should the paper 

 go into print. The proof sheets were not sent to me, and I knew nothing of the fate 

 of the paper, although I had made iui|uiry, until I saw a galling stricture upon it in 

 the American Entomologist. The omission just noted made a logical error of but little 

 moment, for the wliole paper makes its own explanation, but which the Entomologist 

 greedily laid hold of in an article headed, " Ash and Mountain Ash," the main object 

 being to flatter me with the assurance that, after years of botanical study, I did not 

 know to what family Dr. liray assigned the mountain ash, all of which you can read 

 at your leisure, as I do not care to copy any of it or make furtlier comment. In my 

 paper on " The Apple Bark Louse " in the Transactions of the American Entomologi- 

 cal Society, Jan., 1868, I gave a minute description and date of observations of the 

 method of propagation. I followed the insect, day after day, from its fii'st hatching on 

 the 9th of June, through every phase of its development to the perfect state. After 

 about two months they commenced laying their eggs, and continued egg laying tor 

 about one month, having finished their work, died. 



In my paper already alluded to in the Trans. 111. State Hort. Society for 1868, I have 

 given very precise data regarding the distribution of the bark louse, and prove that they 

 spread chiefly by instrumentahty of winds, by crawling on the ground and other ob- 

 jects, and to this I will add, running water may^carry the young bark louse a great dis- 

 tance during a shower, and it yet survive and ascend a tree. During the last summer 

 I have observed that a creek transported young lecanium insects a long distance, and 

 gave them access to trees of a different species on which they developed successfully. 



Regarding the methods and instrumentalities that restrain the spread of the "Apple 

 Bark louse ''much has been said on all sid(^s. "Washes and applications of various 

 kinds, patented and otherwise, have been resorted to, many of which, especially the 

 alkaline washes, have proven useful, and l)ut for the difficulty in applying them at the 



