ANT-XESTS. 221 



never seen a large larva being made use of. The soft and tiny grubs 

 are held by the larger ants, who slowly move up against those pulling. 

 Each grub is held by the middle, with head pointing forward, its snout 

 is gently made to touch the edges of the leaves where they are joined, 

 it is slowly moved backwards and forwards and is undoubtedly issuing 

 a thread during the operation, which adheres to the leaf edges, and 

 eventually grows into the web. When this web is completed it must be 

 composed of several layers to be strong enough for the purpose of 

 securing the leaves. Whether the larva is an unwilling instrument or 

 not in its captor's mandibles is a point which cannot be ascertained. 

 Maybe it is. for it cannot be comfortable in such a position. However, 

 it supplies the web; perhaps if it were not robbed of the web for the 

 benefit of the community it would be able to spin a cocoon for itself, 

 in which to undergo the delicate change into the pupa state, for I 

 have never seen a cocoon, all pupae being quite naked. 



" When contemplating the work done in these nests one cannot but 

 marvel at the wonderful ingenuity displayed, or in endeavoring to 

 form some idea of the vast number of larva? which must be utilized to 

 supply the connecting web even for a moderately sized nest, for with 

 trees with narrow leaves, like Eucalpytus tcssclaris for instance, many 

 scores of leaves are required to form a nest, and each must be sewn." 



Without knowing of these various observations on the Old World 

 (Ecophvila, Goeldi discovered the same method of nest-weaving in the 

 Brazilian Cuiiiponotns senex. His observations together with a figure 

 of a nest of this ant, have been published by Forel (1905^). Similar 

 observations made by Jacobson (1905) on Polyrhachis dives (edited by 

 Wasmann, 1905) and by Karawaiew (1906) on P. initellcri and ale.v- 

 andri prove that the silken nests of the ants of this genus are also spun 

 by the larva. The latter author has described the complicated and 

 voluminous sericteries in the larvae of P. mucllcri (Fig. 124.4). Thus 

 we have indisputable proof that the ants of three different genera, in- 

 habiting the tropics of both hemispheres, have acquired the extraordi- 

 nary habit of employing their young as instruments, or utensils, in the 

 construction of their nests. Here, as in so many other instances, 

 organs and functions originally developed for a very different purpose 

 in this particular case for spinning the pupal cocoon have been 

 adapted and transferred to a very different purpose. 



Nests in Unusual Situations. In this category we may include ant- 

 nests in human dwellings, ships, etc., tenanted by such species as Mono- 

 inoriuin pharaonis and destructor, Pheidole megaccphala, Solcnopsis 

 molcsta and Prenolcpis longicornis. These, of course, originally lived 

 in nests in the soil, but on becoming house-ants they took to the crevice? 



