DESTRUCTIVE INSECTS. 291 



become stationary and large, by forming a shield over 

 tbeir bodies, under which they bring forth and rear 

 their numerous progeny. It has been questioned, 

 whether the scale, from under which the young ones 

 come forth, be or be not a part of the body of the 

 mother. If raised from the leaf by the point of a 

 knife, there appear to be six legs, or tentacula spread 

 out, three on each side, of a whitish colour, partly 

 attached to the shell, and also to the leaf; but 

 may not this covering be formed of an exudation 

 from their bodies, by which their young are pro- 

 tected? 



Another but much larger scale coccus is occasion- 

 ally found in hot-houses, on peach trees, and vines. 

 This is, perhaps, what is called the vine-fretter. Their 

 economy is like the last, only with this difference, 

 that as their young increase in size, the lower edge 

 of the shield is raised up, and the progeny are 

 suspended in a white silky web as large as a middling 

 pea, from which they issue forth when able to provide 

 for themselves. 



Besides these cocci common in gardens, two others 

 are found in woods and hedges, one of which, coccus 

 arborea, has lately found its way into gardens, seating 

 itself on pear and apple trees, which it weakens con- 

 siderably. In underwoods they attach themselves to 

 the bark of red willow and ash-poles, closely congre- 

 gated together on the lower part of the stems. One 

 of these has oval, the other kidney-shaped scales, or 

 dorsal shields, about two -thirds of a line in length. 

 u2 



