168 



Insect Pests. 



A faint, white membrane is seen around the edge of the scale in 

 some specimens. At the pointed end, we notice a smaller scaly 

 area, marked oft' from the larger. This is the insects' cast skin, 

 the so-called exuvium. 



If we lift up one of these scales on the apple tree with the point 

 of a knife some time during the late summer, turn it over and look at 

 it with a magnifying glass, \ve shall at once see lying at the front 

 end of the scale, a small pale, fleshy mass, which has distinct lines 

 across it. This is the female insect, which has formed, as we shall 

 see, the tiny scale above to serve as a protecting house. With the 

 point of a pin this legless, wingless, feelerless, female can easily be 

 taken from under the scale, and can be more carefully examined. 

 With the aid of a strong magnifying glass her body will be seen 

 to be somewhat oblong in form. One 

 will notice that there are no traces of any 

 organs of locomotion or any marked external 

 segmented structures, such as the feelers. 

 But in front, we shall see the mouth, 

 which is in the form of long, thread-like 

 structures, often much longer than the 

 body of the insect. This long, thread-like 

 organ is forced deep into the tissue of the 

 apple tree, and by it the sap of the tree is 

 drawn up into the scale insect's body. 

 Now we must show a little patience and 

 search, perhaps for some hours, amongst 

 the scales on the apple trees to look out 

 for the much rarer scale of the male insect. 

 The male scale can be told from the female 

 by its much smaller size and squarer build. They cannot always 

 be found. 



If we keep examining the mussel scales on the apple tree into the 

 winter, we shall find that by degrees the female body become smaller 

 and smaller, and eventually remains behind as a shrivelled mass of 

 skin under the scale. As the female shrivels up, we find gradually 

 accumulating, at the broad end of the scale, small oval, grey bodies, 

 looking like dust. These are the eggs of the insect, of which as 

 many as eighty may occur under each scale, but often only thirty 

 to forty, in this country. In fact, the female becomes merely a bag 

 of eggs, and so has carried out her sole function, that of continuing 

 her species. In June, we find that these dust-like eggs hatch out 

 into little active creatures, provided with six short legs and two 



IF. E. 



FIG 140. PROPUPAL STAGE OF 



A MALE SCALE INSECT. 



(X 15.) 



