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 a way 



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. 



691. Some Insects, although passing through the complete se- 

 ries of transformations of which we have first spoken, appear, to a 

 certain extent, 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 



1'I'J. 434. EPHEMERA VCLGATA ; LARVA, FUI'A, AN1) IMAGO. 



