ants' nests. 371 



existence are entirely different there from those of the primeval 

 forest ; and, in the second place, because other ants frequently 

 take possession of their dwellings in the Myrmecodia bulbs, and 

 act as their representatives. Treub found no dangerous foes of 

 Myrmecodia in the botanical garden, but in the forest it can be 

 eaten or otherwise destroyed by mammals or other animals which 

 are kept at a distance by the ants. Scepticism is necessary and 

 good, but denial and rejection are not good without sufficient 

 reasons. 



In a shrub in Borneo, Clerodendron fistidosum^ Beccari, Beccari 

 constantly found a Colobopsis, which Emery has named Colohopsis 

 clerodendri. Here the plant, which, like the Cecropia, has hollow 

 internodes, likewise forms a round, attenuated spot in its walls, 

 which is bored through by Colobopsis, and serves it as a door. 

 The plant also possesses innumerable extrafloral nectaries (that is 

 to say, glands producing a sugary liquid, which lie, not in the 

 flowers, but in other places). Still, I am not yet entirely con- 

 vinced, in this case, that there is an adaptation on the part of the 

 plant, because the species of the genus Colobopsis, so far as 

 hitherto known, are shy and cowardly, and would, consequently, 

 furnish no protectors to the plant. The similarity of the shape of 

 the head of the soldier of this species seems to me to indicate 

 that he stops up the round opening of the nest in the stalk of the 

 Clerodendron, with his head, in the same manner that the soldier 

 of our European Colohopsis truncata stops up the door of his wood 

 nest. All investigations on this subject, as well as on the ant's 

 mode of feeding, are still wanting. 



There are, besides, a number of similar incomplete or doubtful 

 relations, noticed especially by Beccari, as, for example, that of the 

 palms of the genus Korthalsia to Campoiioius hospes^ Emery, and 

 korthalsice, Emery; that of plants of the genus Triplaris to various 

 ants which inhabit their stalks, etc. ; but minute investigations 

 of them are still wanting. The future will yet bring us many 

 surprises. 



(c) Casual relations. — We have already become acquainted 

 with these in that kind of nest in which the ants make use of 

 natural cavities. Hollow acacia thorns are also frequently used as 

 dwellings by ants which elsewhere make their nests in an entirely 



