Caterpillars. 193 



in which the whole brood lives, eats, and undergoes the 

 usual transformations. The shape of this tent, for the most 

 part, approaches the pyramidal, though that depends much 

 upon the natural growth of the herbage which composes it. 

 The interior is divided into compartments formed by the 

 union of several small tents, as it were, to which others have 

 been from time to time added according to the necessities of 

 the community. 



When they have devoured all the leaves, or at least those 

 which are most tender and succulent, they abandon their 

 first camp, and construct another contiguous to it under a 

 tuft of fresh leaves. Several of these encampments may 

 sometimes be seen within the distance of a foot or two, when 

 they can find plantain (Plantago lanceolata) fit for their 

 purpose; but though they prefer this plant, they content 

 themselves with grass if it is not to be procured. 



When they are about to cast their skins, but particularly 

 when they perceive the approach of winter, they construct 

 a more durable apartment in the interior of their principal 

 tent. The ordinary web is thin and semi-transparent, per- 

 mitting the leaves to be seen through it ; but their winter 

 canvas, if we may call it so, is thick, strong, and quite 

 opaque, forming a sort of circular hall without any par- 

 tition, where the whole community lie coiled up and huddled 

 together. 



Early in spring they issue forth in search of fresh food, 

 and again construct tents to protect them from cold and 

 rain, and from the mid-day sun. 



M. Ke.aumur found upon trial, that it was not only the 

 caterpillars hatched from the eggs of the same mother 

 which would unite in constructing the common tent ; for 

 different broods, when put together, worked in the same 

 social and harmonious manner. We ourselves ascertained, 

 during the present summer (1829), that this principle of 

 sociality is not confined to the same species, nor even to 

 the same genus. The experiment which we tried was to 

 confine two broods of different species to the same branch, 

 by placing it in a glass of water to prevent their escape. 



o 



