174 NATURE TEACHING. 



larvae and pupae resemble the perfect insect, 

 but they have no wings in their early stages 

 and only rudimentary ones later, the perfect 

 insect being completely winged. Many of 

 these plant-bugs emit very unpleasant odours 

 when handled. 



3. The scale-insects belong to the plant- 

 sucking class of insects. They are usually so 

 peculiar in appearance that it is difficult to 

 recognise that they are insects. If the twigs 

 and underside of the leaves of many plants such 

 as the lime, orange, mango, guava and avocado 

 pear be examined, there will often be found 

 white or brown scale-like bodies, firmly attach- 

 ed to the plant. These vary much in shape, 

 colour and general appearance, being often 

 brown or white. Some are covered with a 

 hard leathery shell, or cottony down, or again 

 with a waxy secretion, while others have little 

 covering. Under the scale or covering, the 

 insect lives with its beak or proboscis fixed in 

 the plant and sucking out its juices. The 

 female insect has no wings, and when once 

 fixed on any spot rarely moves from it; here 

 the eggs are laid and are often to be seen in 

 great numbers beside the body of the parent 

 insect, underneath the scale which covers them 

 both. The male insect becomes winged, and 



