Stone-Mason Caterpillars. 247 



uncommon on old walls. Reaumur observed them regularly 

 for twenty years together on the terrace- wall of the Tuileries 

 at Paris ; and they may be found in abundance in similar 

 situations in this country. This accurate observer refuted 

 by experiment the notion of M. de la Voye that the cater- 

 pillars fed upon the stones of the wall ; but he satisfied 

 himself that they detached particles of the stone for the 

 purpose of building their tents or sheaths (fourreaux), as he 

 calls their dwellings. In order to watch their mode of 

 building, Reaumur gently ejected half-a-dozen of them from 

 their homes, and observed them detach grain after grain 

 from a piece of stone, binding each into the wall of their 



Lichen-Tents and Caterpillars, both of their natural size and magnified. 



building with silk till the cell acquired the requisite magni- 

 tude, the whole operation taking about twenty-four hours 

 of continued labour. M. de la Voye mentions small granular 

 bodies of a greenish colour, placed irregularly on the ex- 

 terior of the structure, which he calls eggs ; but we agree 

 with Reaumur in thinking it more probable that they are 

 small fragments of moss or lichen intermixed with the stone : 

 in fact, we have ascertained that they are so. (J. R.) 



When these little architects prepare for their change 

 into chrysalides before becoming moths, they attach their 

 tents securely to the stone over which they have hitherto 

 rambled, by spinning a strong mooring of silk, so as not 

 only to fill up every interstice between the main entrance 

 of the tent and the stone, but also weaving a close, thick 



