LABV^ OF WATEE-PLIES. 255 



of their flight. The females as they fly deposit their small 

 oval eggs in the water, which sink and adhere to stones and 

 aquatic weeds. The larvse, which in due time are hatched 

 from these eggs, do not bear much resemblance to the full- 

 grown insects. Their bodies, which are flat and elongated, 

 have three long feather-like appendages at the extremity of 

 the abdomen. At the sides of the abdomen there are some 

 leaf -like branchial organs attached in pairs to all the segments 

 of the body except (according to species) the last three or 

 four. The antennae are long and bristle-like. The larvae and 

 pupae have strong mouths, and feed by preying upon small 

 aquatic animal life. For a long time it was quite a matter 

 of doubt what was their proper food. Some authorities 

 declared that because their bodies, when dissected, were found 

 to contain mud, that they ate mud; while others supposed that 

 they consumed vegetable matter. These larvae construct no 

 cases as do those of the Caddis-fly, but live either freely in 

 the water or in curious burrows made in the banks of the 

 ponds and streams which they inhabit. As a rule, it is the 

 larvae of the larger species of the EphemeridcB which make 

 the burrows. These buri-ows, which axe formed somewhat in 

 the shape of the letter U, are so arranged that the insect can 

 go in at one end and out at the other, and so save itself the 

 inconvenience of turning round within its narrow home. In 

 making the burrows, these creatures seem, in some measm-e, 

 to imitate the common earthworm by swallowing at least a 

 portion of the mud or soil they are excavating. This habit 

 accounts, it is thought, for the presence of mud within their 

 bodies. 



These larvae change their skins frequently as they grow, 

 and are said to become pupae when then- thoraces show signs 

 of beai'ing wings. After a certain time, according to species, 

 the piipa leaves the water and develops into a fly, but, strange 

 to say, not the perfect fly, for there is stUl another change 

 before the imago appeai-s. The sub-imago, as it is called, is 

 the " Green Drake " of the fisherman. It is a slow and clumsy 

 flyer, and^sQon settles upon some spot conveniently situated 

 for getting rid of the pellicle which covers its whole body, and 



