36 POND LIFE 



the stems of water-weeds. The eggs hatch into peculiar larvae 

 very different to the parents. The body is brown and segmented, 

 and the usual three pairs of legs are present : the head, joined 

 to the body by a narrow neck, is broad and flat with cruel curved 

 fangs (mandibles), and on the last segment of the creature's 

 body two fringed tubes are borne, which contain the spiracles 

 and supply the larva with air. 



Similarly to the adult, it must rise to the surface to extrude 

 the end of its abdomen. The creature is well adapted to the 

 life it leads, for its colour makes it difficult to notice, especially 

 when resting on the mud. It obtains food not by chase but 

 by stealth, and concealed by its colour waits until a tadpole or 

 other creature touches it. Then its prey is savagely seized 

 and held in the sickle jaws, through the fine canals of which 

 the liquid portions are drawn up, for the larva, although pos- 

 sessing a mouth, is unable to use it. The young Dytiscus 

 has an insatiable appetite, and so has no sooner dispensed with 

 one victim than it is ready and eager for another. Worms, 

 tadpoles, fishes, newts, larva of its own kind, large or small, 

 full-grown water-beetles, all are slaughtered. For some time 

 the youngster kills and grows, having frequently to change 

 its skin as its size increases, until it reaches the maximum 

 of 1^ inches. 



Although no longer so agile, its savagery has by no means 

 diminished. The hand of the owner, so bravely lowered into 

 the aquarium, if it should be placed within seeing distance of 

 the larva, is not there on a future occasion. For the Dytiscus 

 is a mass of ferocity, eager for the blood of anything that 

 comes its way : nor is it afraid to protect itself by any means. 

 Eventually it becomes less active, and slowly swims to the side 

 of the pond, in order to leave the water for pupating. It 

 buries itself in the mud, and here, in a sanctuary safe from its 

 enemies, rests whilst the wonderful changes that are to make 

 it into the beetle are undergone. 



And one fine day the pupa case is ruptured, and the perfect 

 insect brushes the earth aside, and finds its way back into the 

 pond where its larvahood was spent. The adult, although a 

 carnivorous beast, dearly loving a tadpole or worm, can if neces- 

 sary live happily on vegetable matter, and being by no means 

 a faddist, enjoys freshly dead or living creatures, or even de- 

 composing organic matter. In habits it is much altered. As 

 larva it waited ready to pounce on some unfortunate visitor 

 but when adult it swims sedately until it finds what it re- 

 quires. 



Ascilius sulcatus is a beetle very similar to Dytiscus. Its 



