ANTS AND PLANTS 195 



Macaranga caladifolia are arranged in a quite hap- 

 hazard way in fact, they occur just wherever the ants 

 desire to effect an entrance. Beccari found ten dead 

 ants in an internode of a specimen of Clerodendron 

 fistulosum which he had dried and pressed for his 

 herbarium ; in this internode there was only one 

 hole, and that was covered over by a leaf. Beccari 

 asks why the imprisoned ants had not gnawed their 

 way out, either through the leaf covering their solitary 

 exit or through the wall of the internode at the point 

 where the other hole ought to have been a point 

 marked by a circular patch of softer tissue. If 

 we make the obvious answer that the ants did not 

 bore their way out because they were not able to 

 do so, we must then assume that ants do not make 

 the holes which are found in the internodes, but that 

 these as well as the cavities are part of the normal 

 structure of the plant. 1 Then immediately arises the 

 question for what purpose are these holes and cavities 

 formed ? 



Many rattans of the genus Korthalsia have a special 

 organ which seems to be adapted for harbouring ants. 

 It is known as the ocrea, an appendage of a leaf- 

 sheath which may be likened roughly to an upturned 

 flat-bottomed boat. One species attracted Beccari's 

 attention by a peculiar sibilant rustling, which was 

 produced by the passing of ants over the ridged and 

 dry ocrea, which acted like a sounding-board. The 

 ocrea is very closely pressed to the stem of the 

 rattan, and in order to get underneath it the ants 

 have to bore holes through it. These holes may be 



1 The openings into the stems of Macaranga and Clerodendron 

 are made by the ants themselves. H. N. R. 



