178 



In dealing with tlieso pests on cultivated plants, a .indicious prnnins or 

 thinning out should be the tii-st step taken ; in winter the treatment advised 

 for the oyster-shell bark-louse is effective, and any tliat escape may be easily 

 destroyed in the early summer, when the young lar\a' emerge from the eggs, 

 by using either of sprays No. 2, G, or 7, as directed. But it must be borne in 

 mind that, to be effective, this summer spra.ving must be done before the 

 insects have jirotected tliemselves with defensive scales. 



OySTER-SIIEI.I, P.AHK-LOUSE OR SCALE ( M j/t ildxpi s llllliu iriUII . I'.OKK'IIE. ) 



Apple-tree Bark-louse. 



This pe.st occurs In the form of minute scales, about one-sixtli of an inch 

 loug. of a brownish or grayish colour, closely resembling that of the hark of a 

 tree, and somewhat like the shell of an oyster in shape, adhering to the surface 

 of the bark, and placed irregularl.v, most of them lengthwise of the limb or 

 twig, with the smaller end upwards. In most instances the branches of apiile 

 trees may be found literally covered and crowded with these scales; and 

 where thus so prevalent they seriously impair the health and vigour of the 

 tree, ami sometimes cause its deatli. 



Under each of these scales will be found masses of eggs var.ving in 

 number from fifteen or twenty to one hundred or more. These, during the 

 winter or early spring, will lie toiuid to be white in colour, but before hatching 

 they change to a .vellowish hue, soon after which the .voung insects appear. 

 This usually occurs late in May or early in June, and if the weather is cool 

 the young lice will remain several days under the scales before dispersing over 

 the tree. As it liecomes warmer, they leave their shelter and may be seen 

 roving about looking for suilalile locations to which to attach tliemselves. 

 Their actual length being only about one hundredth of an inch, to the unaido>d 

 eye they .appear as mere specks. When highly magnified they appear as at 2. A 

 large iiroportion of them soon become fixed around the base of the side shoots 

 of the terminal twigs, where, inserting their tiny sharp beaks, the.v subsist 

 upon the sap of the tree. In a few days a fringe of delicate wax.v threads 

 issues from their bodies, as at 3. Gradually the insect assumes the form 



