160 INSECT ARCHITECTURE. 



selects grains of mortar, brick, or lichen, fixing tliem, by 

 means of silk, firmly into the structure. As some of these 

 vaulted walls were from an inch to an inch and a half 

 long, and about a third of an inch wide and deep, it may 

 be well imagined that it would require no little industry 

 and labour to complete the 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 cater- 

 pillar 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, cover- 

 ing 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 Eeaumur, as remarkable in 

 his moss-building caterpillars, is equally observable in that 

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

 face of the wall, it would be impossible for a person unac- 

 quainted with those structures to detect where they were 

 placed, as they are usuall}^, 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 repair- 

 ing the breach, by piecing in bits of mortar and fragments 

 of lichen, till we can scarcely distinguish the new portion 

 from the old. 



