24 



STRUCTURE OF THE LEPIDOPTERA 



authoritative observers, the lining of the digestive organs, which is 

 really a continuation of the outer skin, is east off (or rather cast 

 out) at the same time, as are also the linings of the larger breathing 

 tubes which are presently to be described. 



We have seen that some caterpillars, on quitting their egg cases 

 (which may really be regarded as the first moult), make their first 

 meal of the old covering. So also some of them, in their future 

 moultings, exhibit an apparently useless economy (seeing that they 

 are surrounded by an abundance of their 

 natural vegetable diet) by devouring their 

 old coats ! In the face of this fact we can 

 hardly describe them as strict vegetarians. 



Having thus passed through its first hard- 

 ship, the caterpillar has by no means seen 

 the end of the troubles and dangers that beset 

 it ; for, during its existence in the larval state, 

 it has to go through a series of three, four, five, 

 or even six moults, all of which are periods 

 of considerable inconvenience, and perhaps 

 even pain, and frequently prove fatal. And 

 it is by no means an uncommon thing to 

 meet with the lifeless body of an unfortunate 

 individual who, as shown by its shabby 

 appearance and the silken carpet under its 

 feet, has evidently fallen a victim to the 

 dangerous process of ridding itself of an old garment. 



But this is only one of the many dangers to which caterpillars 

 are exposed. Throughout every hour of the day the sharp and 

 hungry eyes of the numerous insect-eating birds are searching the 

 leaves for such delicacies to satisfy the wants of themselves and 

 their broods. The lively little lizards, too, during the sunny 

 hours are busily engaged in searching them out among the foliage 

 of heaths and banks. 



Very formidable enemies also exist in the form of Ichneumon 

 and other species of flies, which pierce the skins of caterpillars with 

 their sharp ovipositors, and lay their eggs within the bodies of 

 the unfortunate victims. As soon as the young larvae are hatched 

 from these eggs, they commence feeding on the fatty substance 

 stored beneath the caterpillar's skin. They carefully avoid, at 

 first, attacking the vital organs of their host's body, and in this 

 way secure for themselves a more lasting supply of fresh food, 



FIG. 16. THE CATER- 

 PILLAR OP THE 

 PURPLE EMPEROR 

 BUTTERFLY. 



