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miscible oils, believing that bj an alternation of the two ma- 

 terials better results are obtained. Whatever the material 

 used may be, the spraying should be thorough, and every 

 part of the tree covered with the spray. If windy weather 

 prevents good work, it is often possible to spray one side of 

 the trees and complete the treatment at some later time. 



Sometimes summer treatment seems advisable on trees 

 badly affected. In such cases either of the above materials 

 can be made use of, though they should be diluted much more 

 than for winter use. 



Many other trees besides fruit trees and many shrubs are 

 attacked by the San Jose scale, but the treatment for these is 

 the same as that given above. 



The Oystee-shell Scale. 



This common pest on apple, pear, ash, poplar and willow 

 trees and lilac bushes is much larger than the San Jose scale, 

 and is of different form, being long, rather pointed at one 

 end and broader and rounded at the other, and may be curved 

 along its length, the form as a whole suggesting that of an 

 oyster shell, which has given it its name. It is brown or 

 dull gray in color, this last shade being the most common on 

 the ash, willow and lilac. 



The life history of this scale is so different from that of 

 the San Jose scale that the treatment for it is also very dif- 

 ferent. 



The winter is passed by this insect in the egg. At this 

 time the parent insect which produced the scale lies dead 

 under the pointed end of the scale, and the rest of the space 

 is occupied by from twenty to a hundred tiny whitish eggs. 

 These hatch about the first of June, and the young, which are 

 whitish-yellow, and closely resemble the young of the San 

 Jose scale, push out from beneath the parent scale and crawl 

 about, seeking for a place to settle and feed. When this has 

 been found a scale begins to form over the back of the insect, 

 and by October it has become fully grown, has laid its eg^s 

 behind it under its scale and has died. These eggs pass the 

 winter and hatch the following June. 



