166 



Insect Pests. 



different kinds of trees. TTe find the Mussel Scale, for instance, 

 on apple, pear, plum, cherry, currant, nectarine and peach, on elm, 

 willow, birch, ash, oak, lime, poplar, cornus, roses, hazel, cob and 

 filbert nuts, and now and then on gooseberries. Fernald (1) gives 

 also for abroad such food plants as butter-nuts, Stillingia sebifera, 

 Ailautlms glandulosus, Ceanothus americanus, Sassafras officinale, 

 .Esculus glabra, Syringa persica, Cysticus, etc. 



This insect is found in nearly all countries where apples and 

 pears are grown. It is very abundant in Xorth America, in Africa, 



01. T. D. Kintoul. 



FIG. 138. THE MUSSEL SCALE (LepidoSdpheS tt/Wll, OX APPLE TWIG. 



in Australia, and New Zealand. It has been distributed by means 

 of nursery stock, and in many of our colonies, etc., its importation 

 is now guarded against by legislation (2). 



Normal bark gland markings must not be mistaken for Scale 

 Insects (Fig. 141) (5). 



LIFE-HISTORY, HABITS AXD STRUCTURE. 



To find this scale insect we should go to an old orchard, and 

 examine the trunks of the trees, when a casual search will soon 



