ARCHITECTURE OF MOTHS. 81 



two surfaces that compose it, before they commence 

 joining them together ; and the serrated incisions 

 made by the mandibles have the tendency to support 

 the opposite edges, by interlacing with each other, 

 so as to support the disjoined portions until they are 

 properly secured. Those Tinese, however, which 

 eat out their habitations from the edge of a leaf, 

 cannot proceed upon the same principles, for, if they 

 were to separate the inner side before they had 

 joined the two pieces, both the architect and his 

 building would come down. Before making the 

 incision, therefore, they baste (to adopt a phrase 

 used by tailors) together in remote points the two 

 membranes on that side. Then, by thrusting out 

 their head, they separate, with their forceps, the 

 intermediate portions, while they take care to avoid 

 touching the larger nerves of the leaf. When this 

 operation is gone through, they proceed to sew up 

 the detached sides in a more regular style, while they 

 only intersect the nerves, which completes their 

 ingenious task.* 



Some other caterpillars form their dwellings entirely 

 of silk, and similar in its general plan of con- 

 struction to that last described, except in point of 

 the material with which it is composed, and, like it, 

 feeds on the parenchyma of the leaf alone. Pear 

 trees are much infested with these minute Iarva3 ; 

 and, in spring, they frequently beset the whole under 

 side of the leaves with their abodes ; these are of a 



* REAUMUR, iii. 100-120. 



