154 THE MAYFLY. 



May-flies in the wide sense. The family is 

 often ranked within the Pseudo-neuroptera sub- 

 order of Orthoptera, not far from Dragon-flies. 



A thin delicate body, with filmy wings, of 

 which the anterior are much the larger and 

 sometimes the only pair : rudimentary mouth- 

 parts in the adults, which fast throughout their 

 short aerial life : a long lived voracious larval 

 existence in the water, with so called tracheal 

 gills for aquatic respiration, are stFiking features 

 of the Ephemerids. 



The antennae are short and awl-shaped; the 

 eyes of the males are very large; the head- 

 shield is enlarged, covering the rudimentary 

 mouth-parts; the middle ring of the thorax is 

 exaggerated ; the legs are delicate ; the thin 

 abdomen ends in two or three long filaments. 



The life history of these delicate ephemeral 

 insects is very interesting. The eggs are laid 

 in the water and give rise to aquatic larvae, 

 which live sometimes two or three years, 

 moulting many times. 



They prefer running water, hide under stones 

 or make burrows in the mud, have well 

 developed mouth-parts, and feed hungrily 

 enough on other insects. The tracheae or air- 

 tubes are expanded in plate-like or tuft-like 

 paired structures down the sides of the posterior 

 body. 



A pupa stage eventually follows, during which 

 the larva acquires wings and other adult 

 structures, but the insect which emerges and 

 leaves the water is, curiously enough, not yet 



