COCOON OF THE PUSS MOTH. 465 



constructed of silk, the bark chips being merely added to it in 

 order to make it agree in appearance with the trunk of the 

 tree. Moisture does not soften this silken secretion, though 

 air hardens it, and the consequence is that after exposui'e to 

 the atmosphere, the cocoon becomes as hard as if made of 

 horn, so that the inmate is safe from nearly all enemies ; while 

 the exact similitude between the surface of the cocoon and the 

 bark of the tree renders it almost incapable of discovery. 



A very good specimen of this cocoon in my collection was 

 discovered by me quite accidentally, and so precisely did it 

 resemble the bark of the tree that I was obliged to keep my 

 finger on the spot while I opened my knife, fearing that if I 

 once lost the exact place I should never find it again. If the 

 larva be kept in captivity, and deprived of material from 

 which the wood-chips of the cocoon are formed, it is obliged to 

 form its habitation entirely of silk, and thus enables- the 

 observer to see the construction of this remarkable cocoon. 

 Though formed of silk, it is not made like that of the silkworm 

 Moth, of a thread which is wound into an oval shape. No thread 

 is visible, but the whole cocoon looks (and feels) as if it were 

 made from very thin horn, so translucent that the form of the 

 inmate can easily be seen through it. I imagine that, although 

 the cocoon is spun like that of the silkworm and other Moths, 

 the silk does not harden immediately it comes in contact with 

 the atmosphere, so that the whole mass becomes fused together, 

 and the individuality of the thread is thereby lost. I have 

 reared many of these larvae, and found that, although they 

 would always use portions of their food-plant in the construc- 

 tion of the cocoon, they were really quite independent of it, 

 and did not suffer in any way by being obliged to form their 

 dwelling entirely of silk. 



It is always easy to force a Puss Moth larva to form such a 

 cocoon. When it is full-fed it loses the brilliancy of its 

 colours, a brownish hue comes over its body, and it looks as if 

 it were about to die. It should then be removed from its food - 

 plant, and placed in the glass vessel in which the cocoon is to be 

 preserved for the collection. After the cocoon is fully formed, 

 the vessel should be subjected to the vapour of bruised laurel 

 leaves long enough to kill the pupa, and the dead insect 



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