370 ants' nests. 



several bundles of vessels in the compartments. Treub has, con- 

 sequently, resorted to other attempts at an explanation, and has 

 regarded these singular cavities as the breathing organs of the 

 plant, and connected them with the interior irrigation of their web 

 (the compartments have a very watery web), which, in view of the 

 epiphytic situation of the plant upon trees with little foliage, is 

 plausible. My own opinion, however, is that Beccari's observa- 

 tions are correct, and that the ants lend their aid by connecting 

 some of the cavities by bored passages, as the natural cavities do 

 not all appear to me to have a natural communication with each 

 other, such as the ants require. Furthermore, the founders of the 

 colony, the mother females, must first bore in. At all events, only 

 the adaptation on the part of the ant is well ascertained — that is 

 to say, in the case at least of Iridomyrmex cordatus, which finds 

 its exclusive, beautiful, and secure dwelUng in the plants of the 

 genera Myrmecodia^ Hydnophytnm (and Dischidia ?). Botanists 

 say that these plants furnish no special food to the ants, at least 

 nothing has been found corresponding to the Miiller's corpuscles 

 of Cecropia. Since, however, most of the Dolichoderi keep no 

 plant lice, but lick up the secretions of plants, or devour insects, 

 a closer investigation of the mode of feeding of Iridomyrmex 

 cordatus would probably bring some interesting facts to light. 

 Besides, Treub's observations do not prove by any means that the 

 plant does not form the labyrinth for the purpose of serving as a 

 dwelling for the ants. The fierce inmates certainly afford it pro- 

 tection against its enemies. 



We must investigate, as Schimper did for Cecropia^ whether 

 there are kindred species of plants, not inhabited by ants, with or 

 without similar labyrinths. It remains surprising enough, in spite 

 of Treub's later explanation, that so small a plant forms such a 

 colossal bulb, with such cavities, to which a particular species of 

 ant has so evidently adapted itself. It seems to me that the pos- 

 sibility of an adaptation on the part of the plant cannot yet be 

 decisively denied, and that we should await further investigations 

 into the biology of Iridomyrmex cordatus and Cremastogaster 

 defer mis. The fact that in the botanical garden at Buitenzorg 

 Myrmecodia thrives without Iridomyrmex (Treub) proves nothing, 

 because, in the first place, the conditions of the struggle for 



