HOMES OF SOCIAL INSECTS. 341 



haps in this genus, as among the Polistes, workers are wanting 

 (see Fig. 2). 



The wasps hitherto considered are distinguished as manufac- 

 turers of paper, in general fine and thin and more or less brittle, 

 the weakness of which they overcome by the superposition of a 

 great number of leaves. There is a large class who, while they 

 make many kinds of papyraceous tissues, are noted for a feature 

 in common the fabrication of a solid and tough paper, a veri- 

 table cardboard, composed of only one layer of material, at times 

 very thick and resisting, at others slight and supple. Of this 

 substance, after the manner of Vespa, the wasps usually build a 

 papyraceous envelope or sac for the inclosure of their combs, and 

 as in that genus, the covering follows closely the direction of the 

 plan of the cells. 



The genus Chartergus, one of the important groups of the 

 cardboard makers, includes insects apparently similar which 

 practice two strangely different forms of nidification. The nests 

 of C. chartarius, the most common in collections, are of frequent 

 occurrence in tropical America. Their cardboard is white, gray, 

 or of a buff color, tending to yellow, very fine and of polished 

 smoothness ; at the same time it is strong and so solid as to be 

 impervious to the weather. It can not be urged sufficiently, says 

 Reaumur, that this kind of envelope is indeed of a veritable card- 

 board, as beautiful as any we know how to make. Reaumur once 

 showed a piece to a cardboard manufacturer, and not the slightest 

 suspicion of its real nature was suggested to his mind. He turned 

 it over and over, he examined it thoroughly by the touch, he tore 

 it, and after all declared it to be made by one of his own profes- 

 sion, mentioning manufacturers at Orleans as the probable pro- 

 ducers. The nests may be conical or cylindrical, they may be 

 straight, but more often are somewhat curved ; some are almost 

 globe-shaped, but these varieties are of little importance. The 

 length of a well-sized nest is about a foot ; the largest yet discov- 

 ered was in Ceylon, and measured the astonishing size of six feet. 

 The edifice is pendulous on trees and attached, as it were, to a 

 suspensory ring, which embraces the branch and is tightly im- 

 pasted round it, or, according to Westwood, may be large com- 

 pared with the latter's circumference ; but it is probably a mistake 

 to say that the nest ever swings freely as on a pivot. The in- 

 terior consists of circular concave horizontal platforms of cells, 

 their mouths turned downward, each tier stretching right across 

 like so many floors, and fastened along its entire edge to the walls. 

 Communication is effected by a central opening through the bot- 

 tom and through every tier. When the number of inhabitants 

 becomes very great and a fresh series of cells is added, unlike 

 the British wasps who add to their abodes by a preliminary in- 



