INTRODUCTION. 7 



more species of insects inhabit the Alpine countries of Central 

 Europe than are met with in Spain or Italy. 



When we consider that every species of plant nourishes several 

 different kinds of insects (and in some cases hundreds), and that 

 apart from the number that derive their sustenance, directly or 

 indirectly, from the higher animals, insects prey on each other to 

 a great extent insect parasites attacking other insects in all stages 

 of their existence, many parasites even preying on other parasites ; 

 when we consider all this, we need not be surprised that insects 

 should be exceedingly numerous. About 12,000 species of insects 

 are known to inhabit England; and the adjacent parts of the 

 Continent support a considerably larger number. The total 

 number of insects known to inhabit the world is estimated at 

 present at 222,000; but this must be very far indeed below the 

 real number in existence, for several thousand species of insects 

 are described as new every year. Nor let any one imagine that 

 our British Fauna is by any means exhausted. It is true that the 

 British Coleoptem and Lepidoptera have been so far investigated 

 that a man must work very hard before he can hope to add a 

 new British species to either Order ; but any entomologist who 

 cares to take up one of the less-studied groups of any of the other 

 Orders, may rely on adding a considerable number of new species 

 to the British Fauna, a certain proportion of which will be new 

 to science. Even among our commonest insects the habits and 

 structure of any one species would furnish any person with a 

 taste for such pursuits with sufficient employment for a lifetime. 

 The collector's province may be exhausted in a few years; but 

 the observer's, never. 



The importance of the study of entomology is now so fully 

 recognised that although we have no " State Entomologist," which 

 is an American institution rendered necessary by the immense 

 damage frequently caused to crops by insects in the United States, 

 yet the Foreign Office not unfrequently applies to the Entomological 

 Society of London for information and advice on the invasion of a 

 swarm of locusts, or the reputed appearance of the Phylloxera of 

 the vine in a British colony. The Society then appoints a com- 

 mittee of specialists to investigate the matter, and in due time 

 reports upon it to the Government. 



Crustacea are the only annulose animals which appear on our 

 own tables; but insects furnish important supplies of food in 

 many countries. The Romans regarded their Cossus, which was 



