ANIMAL STUDY 193 



young appear a week or two later, place some mosquito 

 eggs in the jar. These on hatching will provide food for 

 the young dragon flies for a time. As they grow larger, 

 supply any small soft-bodied insects or even small earth- 

 worms, in addition to the young mosquitoes. Still later, 

 small poliwogs will be acceptable to them. Dragon fly 

 nymphs are voracious feeders, and, if their food is not 

 supplied, they will eat one another. Children will be inter- 

 ested in their manner of feeding, breathing, moulting, and 

 locomotion, as well as in the final change when they emerge 

 from the water, make their last moult, and take the adult 

 form. This should occur in May or June; and, if at this 

 time there are no plants with stems projecting above the 

 surface of the water in the aquarium, some reed stems 

 should be placed in it for them to crawl out upon. The 

 children should now be told something about the life of a 

 fully matured insect. Boys know it as the " mosquito 

 hawk," " darning needle," " snake doctor," and " snake 

 feeder." Its first name is deserved, for it does feed upon 

 small insects taken upon the wing; but the last names are 

 misleading, as it sustains no known relations with snakes. 

 Water beetles, both larvae and adults, are interesting 

 objects in aquaria, but they are quite destructive to other 



forms of life with which they are associated 

 Water 

 Beetles * n nature - ^ kept alone they may be fed 



on bits of fresh meat, earthworms, tadpoles 

 of frogs. The larvae, sometimes called water-tigers, should 

 be kept in shallow vessels, as they are air breathers and 

 must be able to reach the surface of the water with their 

 breathing organs. 

 The water boatmen and the backswimmers, two very 



