THE INSECT WORLD. 



59 



Fig. 31. 



Order EPHEMEROPTERA. 



This order includes what are known as ' ' May-' ' or ' * day- 

 flies," the names indicating either the 

 time at which they first appear or 

 the brief period of their adult life. 

 "May-flies" occur most abundantly 

 during spring or early summer, in the 

 vicinity of lakes, ponds, and rivers. 

 They are readily recognized by their 

 fragile body, terminated by two or 

 three long, thread-like appendages, and 

 by their large, frail wings, the posterior 

 much smaller than the anterior. They 

 fly at night, and are readily attracted 

 to light, dozens being often seen hov- 

 ering around a single street lamp. I 

 have seen bushels of them at the base 

 of electric lights on the banks of the 

 Ohio, and the shores of the Great 

 Lakes are sometimes covered with 

 heaps six inches or more in depth, so 

 that the stench from the decaying 

 bodies becomes nearly insupportable. 

 The head is large, the eyes are round 

 and prominent, and the forelegs are 

 conspicuously long and stout ; but the 

 feelers are reduced to mere rudiments, and the mouth parts are 

 atrophied and utterly useless for feeding purposes. 



In the May-flies we have the survival of an ancient type, their 

 generalized structure indicating a low place in the scale of devel- 

 opment. The eggs are laid on the surface of the water and sink 

 gradually to the bottom. From them hatch narrow, elongate- 

 oval, more or less flattened larvae, furnished laterally and some- 

 times at the end of the body with gill-tufts, living in the mud 

 ooze of river and lake bottoms, under stones, or among aquatic 

 plants. They feed on all sorts of minute animal life, and prob- 

 ably also upon the low forms of vegetation on submerged stones 

 or sticks. They grow slowly, moult frequently, and live from 



May-fly and its larva. 



