172 



THE STUDY OF INSECTS. 



Scale, and of many other forms, the scale-like object com- 

 monly seen is not the insect, but an armor beneath which it 

 lives. 



The young insects of this sub-family resemble in general 

 appearance those of other scale insects. Their active stage, 

 however, is much shorter. After crawling about over the 



Img. 212. — Chionaspis pinifolice ; 2, scales on Pinus strobus, natural size, leaves stunted; 

 2«, leaves of P. strobus not stunted by scale insects; -zb, scale of female, usual 

 form, enlarged; 2<r, scale of female, wide form, enlarged; 2d, scale of male en- 

 larged. 



twigs of a tree for a few days, the young scale insect settles 

 upon a suitable place and immediately begins to excrete 

 a cottony substance which soon becomes compacted into a 

 thin pellicle covering the body. As the insect grows and 

 needs to shed its skin, this cast skin is joined to the excretion 

 and forms a part of the scale. This is the bright-colored, 

 nipple-like prominence, seen in the centre of the Pernicious 



