130 THE BROOK BOOK 



water. In warm weather they are active, and when 

 not engaged in replenishing their necessary air sup- 

 ply by frequent trips to the surface of the water, 

 their time is taken up with capturing for food 

 the many other insects smaller or weaker than 

 themselves. The eggs have been found in the 

 stems of water plants. The tiny creature which 

 comes from the egg closely resembles its parents. 

 I obtained a dozen or more of these lively little 

 fellows for my aquarium. They were of assorted 

 sizes and probably were not all brothers and 

 sisters. They were pale in color, almost white, 

 with a touch of bright red. They had prominent 

 eyes, one on each side of the large head, which 

 was set on broad shoulders without the slightest 

 suggestion of a neck. They had no wings, so 

 could not follow their parents from pond to pond. 

 Even when mere babes, these back-swimmers know 

 how to manage the oars. It is well they do, for 

 they meet many dangers. Strangely enough, they 

 may even fall prey to their undiscriminating par- 

 ents. The back-swimmer's code of ethics makes 

 every insect legitimate prey. He couldn't think of 

 spoiling a good meal for relationship's sake. 



I never happened to be present when my back- 

 swimmer's molting time came round. But we are 

 told that both the back-swimmer and the water- 

 boatman grow, as do other insects of their order, 

 by successive molts or changes of skin. They reach 

 maturity, if they escape their enemies, and spend 

 the winter at the bottom, as did their parents. 



After enthusiastically describing these business- 



