52 INSECT TRANSFORMATION 



legs becomes hard and firm. Then vigorously bending for- 

 wards, it catches hold, with its feet, of the front part of the 

 empty nymph-cuticle (b) or the plant-shoot above it, withdraws 

 the rest of the abdomen, and waits for the cuticle of that region 

 as well as the wings to expand, dry, and harden, much as already 

 described for the emerging grasshopper (Fig. 28 c). For some 

 time after it has acquired the power of flying the dragon-fly 

 has not yet assumed the deep colours and developed pattern 

 that characterize its species ; such a relatively newly-emerged 

 insect is defined as teneral. 



Comparing generally the dragon-fly's life-story with the 

 grasshopper's, we notice such a divergence between parent and 

 young that the latter affords a fair example of a larva, in which 

 the true relationship is masked, and we realize that this 

 divergence is emphasized by the larva's aquatic mode of life 

 involving special temporary breathing organs often of much 

 complexity. The life-history may therefore be included among 

 insect transformations. But the dragon-fly resembles the 

 grasshopper in being active through all the larval and nymphal 

 stages, and in displaying visible external wing-rudiments at 

 an early period of its life. 



With the life-histories of the grasshopper and the dragon-fly we 

 may now compare that of a butterfly or moth, 1 which affords, 

 perhaps, the most familiar example of all insect transformations. 

 First of all it will be necessary to consider the structure of the 

 perfect winged insect, so that the contrast between this and 

 the larva or caterpillar may be rightly appreciated. A typical 

 butterfly or moth is a more specialized insect than a grass- 

 hopper, more delicate in build, more perfectly adapted as a 

 flying organism. In general plan of body there is, of course, 

 agreement : the head with its conspicuous feelers, the thorax 

 with its six legs and four wings, the ten-segmented abdomen ; 

 but in points of detail there are some marked divergences. 

 The scaly covering of almost the whole insect, the scales being 

 flattened cuticular elements of the nature of hairs, is a highly 

 characteristic feature. 



The butterfly's head (Fig. 31 A), has large sub-globular 



1 G. Rolleston and W. Hatchett Jackson: "Forms of Animal Life". 

 Oxford, 1888. 



