478 



THE INSECT WORLD. 



or Whirligig Beetles. These are perfect corsairs, whose rapacity- 

 even exceeds that of many of the land Coleoptera. Not contented 

 with devouring one another, when pressed by hunger, with attacking 

 especially the larvae of all aquatic insects, such as the Libellulm and 

 Ephejjierce^ they feed also on molluscs, on tadpoles, and on small fish. 

 It is easy to rear them in captivity. If confined in a small aquarium, 



Fig. 474. — Dytiscus marginalis, male and female, and front leg of male magnified. 



their habits would be much more amusing than a few golden fish, 

 which one meets with everywhere, and which are only good enough 

 to amuse European Scliaabahams. Care must be taken to cover the 

 aquarium at the top with gauze, to prevent the perfect insects from 

 escaping. This tribe is not very numerous nor varied in its forms. 

 An oval body, legs curved and widened into oars, provided with 

 hairs, distinguish the insects which compose it. They imbibe air at 

 the surface of the water. 



The most carnivorous of this group are the Dytisci and the 

 Cybisters. They may be called the sharks of the insect world. 

 Nothing which lives in the water is safe against the voracity of the 

 Dytiscus. They attack small molluscs, young fish, tadpoles, larvjs of 

 insects, and suck greedily the bits of raw meat which are thrown to 

 them. They may be kept in an aquarium for many years by feeding 

 them on animal matter. Their oval-shaped body, with its sharp 

 sides, permits them to cut through the water with great ease — the 

 hind legs serving as oars. They are to be found in stagnant waters 



