78 A BOOK OF INSECTS 



are characteristic in form. The pupa is free. Beetles are 

 found in all parts of the world, and enormous numbers 

 of species have been described. These are grouped in 

 many families, only a few of which can be mentioned here. 



The tiger-beetles (Cicindelidce) are represented in all 

 parts of the world, though they are most abundant in 

 the tropics. They are active, predaceous insects, Avith 

 relatively large heads and long legs. There are several 

 British species, the best known being Cicindela campestris. 

 The larva?, which have enormous grooved mandibles, 

 make vertical burrows in the ground, where they lie 

 in wait for their prey. The ground-beetles (Carabidce) 

 are nearly allied to the tiger- beetles, from which they 

 may generally be distinguished by their heavier build and 

 less prominent eyes. The larva? live for the most part 

 under stones and rubbish, or in the soil, and are inveterate 

 insect hunters ; but a few species are injurious to plants. 



The carnivorous water-beetles (Dytiscidce) are closely 

 allied to the foregoing families, but they are adapted to 

 an aquatic life, although they are able to fly well. Both 

 they and their larva? are very fierce and voracious. The 

 whirligig beetles (Gryrinidce) are an allied family. They 

 propel themselves over the surface of ponds and rivers by 

 means of their paddle-shaped legs ; but their larvae live 

 entirely under the water. The Hydropliilidce are also 

 water-loving insects, distinguished by the great length of 

 their maxillary palpi, which are often longer than the 

 antenna?. Some of the species are completely aquatic, 

 others frequent marshes. The best known British species 

 is the large black water-beetle Hyd?~ophilus piceus. 



The rove-beetles, or " cock-tails " {Staphylinidce), have 

 short elytra not unlike those of an earwig, beneath which 

 the hind-wings are packed when they are not in use. The 

 most familiar example is the " devil's coach-horse " 



