Moss-building Caterpillar. 201 



work ; yet it does not demand more than a few hours for 

 the insect to raise it from the foundation. Like all other 

 insect architects, this caterpillar uses its own body for a 

 measuring-rule, and partly for a mould, or rather a block or 

 centre to shape the walls by, curving itself round and round 

 concentrically with the arch which it is building. 



We afterwards found one of these caterpillars, which had 

 dug a cell in one of the softest of the bricks, covering itself 

 on the outside with an arched wall of brick-dust, cemented 

 with silk. As this brick was of a bright-red colour, we were 

 thereby able to ascertain that there was not a particle of 

 lichen employed in the structure. 



The neatness mentioned by Reaumur, as remarkable in 

 his moss-building caterpillars, is equally observable in that 

 which we have just described ; for, on looking at the surface 

 of the wall, it would be impossible for a person unacquainted 

 with those structures to detect where they were placed, as 

 they are usually, on the outside, level with the adjoining 

 brick-work ; and it is only when they are opened by the 

 entomologist, that the little architect is perceived lying snug 

 in his chamber. If a portion of the wall be thus broken 

 down, the caterpillar immediately commences repairing the 

 breach, by piecing in bits of mortar and fragments of lichen, 

 till we can scarcely distinguish the new portion from the 

 old. 



