AFFECTION FOR THE YOUNG. 523 



29G. 



The economy of the remaining social Hymenoptera differs from that 

 of the ants by their constructing an artificial nest for the reception of the 

 society, and not merely excavating cavities in the earth for this purpose. 

 The wasps, which most closely agree with the ants in their societies, 

 build some their nests in holes in the ground, and others pendant 

 from the boughs of trees. The material they use is wood, either fresh 

 or rotten, which they grind to a fine powder by means of their powerful 

 mandibles, and then moisten it with a viscid liquid, which is probably 

 the secretion of the salivary glands, when they prepare it into thin 

 pasteboard surfaces. The size of the nest varies considerably ; in 

 Polisles gallica it consists of about twenty roundish cells, open beneath, 

 which form a small convex comb, and which is attached to some object 

 at its highest point ; Vespa holsatica affixes a second larger, and some- 

 times a third smaller comb to the first, which are connected together 

 by many perpendicular, tolerably thick pillars, and the whole nest is 

 enclosed by two or three ovate cases, the lowest of which alone enve- 

 lopes all three combs, each of the succeeding ones being about one-third 

 shorter. The entrance to the interior is in the pendant apex of the 

 first envelope. In the nest of Vespa vulgaris, which is placed in a 

 large hole in the ground, the external case consists of a thick, tolerably 

 strong pasteboard, formed of several layers, and the combs are more 

 numerous, the central ones larger, and the entire nest attains about the 

 size of a moderate melon. Others, for instance, the exotic species 

 (Vespa tatua, Lat.), build a very large but similarly pendant nest, 

 the entrance to which is also beneath, and the superior surface is covered 

 with a multitude of conical knobs. Vespa crabro (the hornet) prefers 

 the cavities of trees for her nest : it differs from that of the common 

 wasp both in size, which is that of a moderate gourd, and also that the 

 external envelopes are separated from each other by the space of at 

 least half an inch, whence passages lead from the exterior to the 

 interior ; it therefore appears upon the first glimpse to be covered with 

 large scales. The much smaller nest of Vespa Germanica is very 

 similar, but it is placed in the earth, at about six inches from the sur- 

 face ; the form of the cells is originally, as also in the humble bees and 

 bees, that of a cylinder, which subsequently, by the pressure of the 

 rest, take that of a hexagon. This last regular form of the cells has 

 ever been considered one of the most extraordinary things, and its 



