336 THE WORLD OF ANIMAL LIFE 



It is very difficult to catch a fly, as most of us know from ex- 

 perience. The reason of this is that insects have very remarkable 

 eyes. These are situated on the sides of the head, and are large 

 and compound {i.e. each is divided into a great many different 

 lenses), and so enable their owner to see in all directions. Besides 

 these, some insects have three single eyes on the top of the head. 



For self-protection some are armed with nippers, others with 

 formidable stings, while yet others depend entirely on their power 

 of flight. But some of the more defenceless present a remarkable 

 peculiarity. As they are more preyed upon than those that can 

 defend themselves, they require some means of preserving their 

 species, and they are, therefore, often coloured and shaped like 

 leaves or sticks, the resemblance being very striking when they 

 are at rest. 



The number of species of insects is greater than that of any 

 other class, though very many are not yet known to us. In variety 

 of form and colouring also, the insects are very remarkable, and 

 often exceedingly beautiful. 



HYMENOPTERA 



The order HYMENOPTERA (that is, membrane-winged) is a 

 group of well-known, highly intelligent, and certainly most interest- 

 ing insects. It is a very large group, containing sub-orderj and 

 a good many families, some of which we shall recognize as old 

 acquaintances if we run through a few representative names, 

 as follows: — Saw-flies, Wood -borers; Ants, Wasps, and Bees. 

 Several of these names are certainly quite familiar, and the 

 creatures themselves are no doubt known to many of us. 



If we consider typical specimens of ants, wasps, and bees, and 

 one of the parasitic wasps (the Ichneumon) as an illustration of 

 what the word parasitic means, we shall have a good idea of the 

 general characters of the Hymenoptera. 



