NETJEOPTEEA. 419 



It is still enveloped in a very thin skin, of which a last moult. 



Fig. 390. Larva of an Ephemera. Fig. 391. Pupa of an Ephemera. 



after a few hours, frees it. This skin remains sticking to the 



plant on which the moulting was 



effected, preserving the shape of the 



insect. This moult is peculiar to the 



Ephemerae ; it is the transition from 



the false imago (pseudo-imago) to 



the imago. 



In the same family is the genus 

 Cloelon whose larvae prey on minute 

 insects. The Cloeon diptera (Fig. 

 392), which has only two wings, is 

 often to be met with in houses, 

 resting on the window panes and 

 curtains. All these insects keep 

 badly in collections ; they lose their 

 shape, and their members are so 

 fragile that the least shock suffices 

 to break them. 



The Libellulas, or Dragon-flies, Fig. 392.-cioeon diptera. 



are insects of a well-defined type. The elegance of their shape, 



EE 2J 



