WATER-BtTGS, WATEB-SCOEPIONS, ETC. 237 



an aquarium. It will even, unless properly and regularly fed, 

 destroy its own species. Small fish seem to be its favourite 

 food. It swims under and seizes its victim with its fore- 

 legs, and quickly buries its beak deeply into the poor creature's 

 tissues; nor will the "boatman" relax its hold until it has 

 extracted all the nutriment it can. N. glauca will also feed 

 upon tadpoles, small frogs, and flies, placed upon the surface 

 of the water. Sometimes it will content itself with a worm 

 or a piece of raw meat suspended in the right position. As 

 this insect is able and willing to use its beautiful and interest- 

 ing wings, the vessel in which it is confined should always 

 be kept covered. On no account should the Water-Boatman 

 be placed in the same aquarium with fish. At night-time 

 occasionally it .makes a curious noise. The larva can be 

 distinguished from the full-grown insect by its shorter body, 

 its unseasoned-looking colour, and its want of wings. 



Notoneeta maculata is generally regarded as a variety of 

 N. glauca. It may be known by a blackish band across the 

 lower part of the body and by its spotted back ; hence its 

 specific name. 



The insects belonging to the genus Corixa are more 

 abundant and less rapacious than the species of Notonectw, 

 and they are quite as interesting and ornamental in the 

 aquarium. They are often wrongly called Water-Boatmen, 

 from which they may be quickly distinguished, not only by 

 their shape, but by their swimming with their backs upper- 

 most. These creatures, unlike the Notonectce, do not remain 

 for any length of time near the surface of the water. They 

 spend most of their Ufe either hunting for food or clinging 

 to the stones or weeds at the bottom of the pond or ditch 

 in which they live. Of course, they frequently have to rise 

 for the purpose of taking in a fresh supply of air. It is 

 quite surprising how many insects of this genus one may 

 sometimes capture with a single sweep .of the net. They 

 are not able to swim so quickly as the Water-Boatman. 

 There are more than twenty species of Corixa found in 

 British waters; but some of them are taken only in Scotland, 

 and others in brackish water, such as the ditches near 



