57 
for the preparation of which is given under the cottony maple scale. 
The lime-sulphur mixture should be applied as late in the winter as 
practicable, best just before the opening of the leaves in spring. The 
kerosene emulsion must be applied immediately after the hatching 
process is virtually complete, a point which can only be determined 
accurately by careful observation. If the young are allowed to live 
too long they become covered and protected, after fixing themselves, 
by a waxy scale which the emulsion will not penetrate. It should be 
applied in a strength to contain ten percent of kerosene. Dr. 
James Fletcher, Dominion Entomologist, Canada, recommended 
spraying infested trees with a whitewash made by slaking a pound 
of lime to the gallon of water, one such application to be made in 
fall as soon as the leaves have fallen, and a second immediately after 
the first has dried. This is said to loosen the hibernating scales, 
which subsequently fall from the tree with the dried whitewash. 
The Oyster-shell Scale 
(Lcpidosaphes ulmi Linn.) 
The oyster-shell scale is among the more conspicuous and easily 
recognized of the smaller scale insects of our trees and shrubs, the 
Fig. 61. Oyster-shell Scale, Lepidosaphes ulmi: a. female scale, 
under side, showing insect and its eggs within; 6, same, from 
above; c, same, natural size; d, e, male scale, enlarged and 
natural size. 
