THE STUDY OF INSECT LIFE 27 



cheap form, expressly for purposes of Nature 

 Study. As nearly all aquatic insects, in both 

 the larval and the adult stages of their existence, 

 are to a greater or less degree carnivorous and 

 extremely pugnacious, it is advisable not to 

 introduce too many specimens, or several 

 different species, into one tank, for battles royal 

 will most certainly take iplace, and with most 

 dire results. This is more particularly the case 

 with the various species of Water-beetles, and 

 the larvae and active nymphs of the Dragon- 

 flies. 



Before any insects are introduced into an 

 aquarium, it should be prepared for their recep- 

 tion ; that is to say, the bottom of the aquarium 

 should be covered with a layer of well-washed, 

 fine shingle, and one or two water plants 

 established. When the water plants are seen to 

 throw off small bubbles, so that the water is 

 naturally oxygenated, then the insects should 

 be introduced, and will be healthy and vigorous. 

 Beware how you introduce earth into the 

 aquarium, because many aquatic insects have a 

 happy knack of digging down through the layer 

 of shingle which may have been placed on the 

 top of the earth, and thus converting your clean, 

 bright aquarium into a horrible and turbid con- 

 dition. The best plan is to place the plants in 

 small, shallow pans or bowls, pressing down the 

 well-damped earth firmly, and placing a good 

 deep layer of shingle on the top. If a little care 

 and attention is given to these small but all- 

 important details, all will be well, our insect 

 guests will thrive, and we shall be able to derive 



