The Glow- Worm and Other Beetles 



case we find the same chemical composition, 

 the same formation, like the cup of an acorn. 

 Dimensions apart, the two structures are 

 identical. But no other genus of Longicorn, 

 so far as I am aware, practises this craft. 

 I will therefore complete the classic descrip- 

 tion of the Cerambyx-beetles by adding one 

 characteristic: they seal their metamorphosis- 

 chambers with a chalk slab. 



The similarities of habit go no farther, 

 despite the identity of structure. There is 

 even a very sharp contrast between the meth- 

 ods pursued. The Capricorn of the Oak in- 

 habits the deep layers of the trunk; the Cap- 

 ricorn of the Cherry-tree inhabits the sur- 

 face. In the preparations for the trans- 

 formation, the first ascends from the wood 

 to the bark, the second descends from the 

 bark to the wood; the first risks the perils of 

 the outer world, the second shuns them and 

 seeks a retreat inside. The first hangs the 

 walls of its chamber with velvet, the second 

 knows nothing of this luxury. Though the 

 work is almost the same in its results, it is 

 at least carried out by contrary methods. 

 The tool, therefore, does not govern the 

 trade. This is what the two Cerambyx- 

 beetles tell us. 



Let us vary the testimony of the Longi- 



210 



