ESCAPE OF IMAGO FROM PUPARIUM. 



>23 



performing the important office of inflation, and chiefly as- 

 sisting in eff"ecting the change, so that in a very short period 

 the insect has arrived at its full size, and acquired the utmost 

 perfection of all its organs. 



The wings of lepidopterous insects, as they lie T\ithin the 

 pupa skin, exhibit all the future markings of the butterfly and 

 moth, but of course of a reduced size. The wings themselves 

 appear perfectly flat, and it is difficult to conceive how these 

 organs expand to their full dimensions, all these markings re- 

 taining their relative sizes. The difficulty is, however, reme- 

 died on denuding the vdngs of their scales, when their sm-face 

 is discovered to be entirely formed of an innumerable series of 

 minute \n'inkles, gi^^ng the wings an elasticity, by which we 

 can stretch them to nearly double their size, by moistening 

 them with water. If we imagine the scales to be placed upon 

 the upper edge of each ridge, and that they increase in size 

 as the wings expand, we shall be furnished with a further 

 clue to the solution of this interesting question, as to the mode 

 of expansion of the AA-ings of the Lepidoptera. 



In the aquatic pupa?, which produce aerial insects, it is ne- 

 cessary for the pupa to quit the water previous to putting on 

 the perfect state ; thus the pupa of the dragon-fly creeps up 



Gnat emerging from its aquatic pupa 



the stems of some adjacent plant ; and that of the gnat 

 half protruding its body above the surface of the water, the 



