ORDER II. EPHEMEROPTERA. 



EPHEMERID.E. 



The May-fly, or ''' day-fly," Ephemera (PI. III., Fig. 

 29, p. 73), is so abundant in parts of the country where 

 ponds and lakes occur that teachers may find it a con- 

 venient type. The body is long, and the three regions 

 are loosely connected. The head is broad and short, 

 and the compound eyes are widely separated, stand- 

 ing out prominently on either side. The prothorax 

 (the rings of the thorax are not shown in the drawing) 

 is freely movable. The mesothorax is the largest 

 thoracic ring, and bears the large wings, while the 

 small metathorax carries the small, hind wings. The 

 antennae (Fig. 29, at) are tiny, and the mouth parts 

 have become reduced in size, since the imagos exist 

 only for reproduction, and do not take any food. 



The legs are extremely long ; the first pair (Fig. 

 29, /') is extended forward in a straight line in the 

 drawing, and in this position may be mistaken for 

 antennae ; they are slender, and of little use as legs. 

 The last two pairs are attached to the sides of the 

 thorax, and are not crowded closely together as 

 in the dragon-fly, an insect which the May-fly re- 

 sembles. The venation of the wings is simple, and 

 in some species the posterior pair is wanting. The 

 delicate structure of these organs, together with the 

 ephemeral nature of the insects, has led us to sub- 



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