METAMORPHOSES OP INSECTS. 



113 



insects showing this kind of metamorphosis, the Grasshopper 

 and the Ephemerae or Day-flies. These last display a remark- 

 able peculiarity ; since in general, insects change the skin for the 

 last time, when they pass from the Chrysalis to the perfect state ; 

 whilst the Ephemera experiences one more change, before arriving 

 at its complete form, in which it only lives for the space of a few 

 hours. The larva of the Ephemera lives in the water, and 

 differs very little from the adult, except in the shortness of its 

 limbs, the absence of wings, and by the row of leaf-like ap- 

 pendages which it bears on each side of its abdomen, and which 

 it uses as organs of respiration and of motion in the water. The 

 chrysalis only differs from the larva, by the presence of cases 

 inclosing the wings. At the time when these organs should be 



developed, the in- 

 sect comes out of 

 the water ; and 

 after having flut- 

 tered about during 

 some minutes, it 

 takes its place upon 

 an elevated object, 

 and there performs 

 some violent move- 

 ments, by means of 

 which it casts away 



its enveloping membrane ; it is then only that its limbs attain 

 their full length, and that the body acquires the colours which 

 it will preserve. 



633. Some Insects, although undergoing considerable changes 

 at an early period, do not pass through the complete series of 

 transformations of which we have first spoken ; they appear to 

 stop short in their development, never possessing any wings. 

 The Fleas are thus circumstanced. "When they come forth from 

 the egg, they are destitute of feet, and have the form of small 

 worms of a whitish colour. These larvae are very active, and 

 roll themselves in a circle or a spiral. They soon become of a 

 reddish hue ; and after having lived in this condition during 



FIG. 334. EPHEMERA VOLGATA : LARVA, PUPA, AND IMAGO. 



