FORM, GROWTH, AND CHANGE 65 



grasshopper or dragon-fly, shows a striking peculiarity in the 

 resting, pupal stage and so far as the former is concerned 

 in the unlikeness of the young insect to the parent. This 

 unlikeness too is much more marked in the butterfly than in 

 the dragon-fly ; the caterpillar is truly a larva a young 

 creature whose parentage] and destiny are alike masked by 

 its appearance. Yet the divergence between butterfly and 

 caterpillar must not be exaggerated ; the fundamental struc- 



FIG. 35. WINGS OF A BUTTERFLY PUPA (EuploSd) 



Showing the system of tracheation, the incipient nervures 

 indicated by dotted lines. Sc, sub-costal ; R, radial ; 

 M, median ; Cu, cubital ; A, anal tracheae of nervures, the 

 branches of each system numbered. About thrice natural 

 size. After Tillyard, Proc. Linn. Soc., JV.S.W., XLIV. 



tures of the parent even to wings and reproductive organs 

 are in the offspring, though in an undeveloped or degenerately 

 modified form. Lastly we notice that, while in the growth 

 of grasshopper and dragon-fly outward wing-rudiments appear 

 at an early stage, these structures are in the caterpillar directed 

 inwards, and thus they remain hidden until the formation of 

 the pupa brings to pass the due time for their appearing. 

 5 



