Aquatic Insects 97 



all the members of which are aquatic 

 and others, very great in numbers, that 

 have only a few aquatic species, the 

 majority being terrestrial. 



Contained in the first group, the so- 

 called wholly aquatic insects, are many 

 interesting forms and of these some of 

 the beetles (Coleoptera) are specially 

 worthy of mention. 



There is one found commonly in ponds 

 in this country. It is quite a large 

 insect, being a little over an inch in 

 length. Carnivorous in habit and known 

 scientifically as Dytiscus marginalia and 

 popularly as the ' Voracious Water 

 Beetle," it justifies the latter name by 

 catching and devouring many of the 

 smaller and less well protected denizens 

 of the pond. Dytiscus is a strong 

 swimmer, the hind pair of legs being 

 especially adapted for the purpose and 

 are used together after the manner of 

 oars. The females have the wing-cases 



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