THE SCALE INSECTS 



(Family Cocci dee.) 



The insects of this family, popularly known as scale insects 

 or bark-lice, include forms of great morphological interest as well 

 as very many of great economic importance. In the latter respect 

 they form very injurious enemies to most fruit trees as well as to 



Fig. 142. — Diaspis pentagona. (Author's illustration.) 



many other shade and ornamental trees. They occur upon 

 bushes and vines as well and are even in some instances found 

 upon grasses. The group as a whole is a most abnormal one in 

 its life history. In general terms it may be stated that the eggs 

 are laid by the adult female either immediately below her own 

 body or at its posterior extremity. Certain species do not lay 

 eggs but give birth to living young as do the plant-lice. This 

 abnormal habit is not characteristic of any particular group of 

 forms but is found with individual species in one or more genera. 

 The young on hatching from the eggs are six-legged, mite-like 



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