142 CLASS-BOOK OF ZOOLOGY. 



ponds, whither they come to deposite their eggs in the 

 water. 



§ 590. The larvae of the different species of the Dragon- 

 fly live in the water more than two years, until they are 

 changed into a perfect insect. 



§ 591. As the Dragon-fly does not injure our vege- 

 tables, and feeds, in its perfect as well as larva state, 

 only upon other insects, it may be regarded as useful. 



§ 592. The Ephemera Fly, called also May-fly and 

 Day-fly, (Ephemera,) is about an inch long ; generally has 

 transparent wings, (those of some species being citron- 

 colored,) which, when sitting, it elevates vertically, like 

 a Butterfly. 



§ 593. As many species of the May-fly, principally 

 those with transparent wings, live only one day when 

 in a perfect state, they have been called Day-flies. 



§ 594. But for the shortness of its life, this creature is 

 indemnified by the length of its existence in the larva- 

 state, which lasts from two to three years, in the water, 

 like that of the Dragon-fly. 



\ 595. Millions of Day-flies are sometimes seen in the 

 month of May, flying about the surface of rivers and 

 ponds, for the purpose of depositing their eggs ; but im- 

 mediately after, they place themselves upon walls, trees, 

 fences, or windows, and die. 



\ 596. The most singular fact in regard to the May- 

 fly, and which is observed in no other insect, is that they 

 cast their skin just before they die. 



\ 597. The Ant-lion (Myrmeleon) is about an inch 

 long, has long drooping wings with dark brown spots, and 

 short club-shaped antennas. 



5 598. The larva, or real Ant-lion, is ill-shaped, thick 

 and short, about three-quarters of an inch long, brownish- 

 gray, and is armed with jaws, similar to a forceps. 



\ 599. The Ant-lion digs a funnel-shaped pit in the 

 sand, and, covering itself to the neck, lies in wait for, 

 and destroys the ants and other small insects, which, not 

 perceiving it, slip in over the loose sand. 



