i76 ROUND THE YEAR 



maxillae are intended to cohere by innumerable 

 hooks, and so to form the long suctorial proboscis, 

 by which the Butterfly will search the depths of 

 nectar-bearing flowers. 



Swammerdam came very near the truth in his 

 positive statements about the tranformations of In- 

 sects, but his knowledge, like that of every first 

 explorer of a very difficult subject, was incomplete on 

 many points. Having found that the caterpillar just 

 before pupation encloses what may be called a Moth 

 or Butterfly, he concluded that the Moth or Butterfly 

 had been there from the first, and that no more im- 

 portant change was involved than the expansion and 

 at length the liberation of the imago. We now know 

 that much goes on of which Swammerdam had no 

 notion. The organs of the imago are not all present 

 from the first. The rudiments of the wings form very 

 early, even before the egg is hatched, but the antennae, 

 the mouth-parts, and the legs of the imago are formed 

 after the last larval moult. Moreover, there is de- 

 struction of old parts as well as formation of new 

 ones. The muscles of the larva, the silk-glands, and 

 various other parts which are not required after the 

 larval stage has come to an end, disappear altogether. 

 The organs which are external, and belong to the 

 outer cuticle, are simply cast at pupation, but what 

 becomes of the internal organs which are no longer 

 wanted ? How do these disappear ? 



They are eaten up and converted into granules, 

 which serve for the nutrition of the rapidly growing 

 organs. Certain wandering cells, very like the colour- 

 less corpuscles of human blood, do the work. The 



