3884: MR. H. H. W. PEARSON ON SPECIES OF 
alinost describe the state of affairs in the pitchers of D. pec- 
tenoides and of Motley’s Bornean plant. The outer pitcher 
of the latter was “crammed” with roots, among which were 
the dead bodies of numerous ants and a large quantity of dark- 
coloured soil. The inner pitcher was full of ants*, a few 
of which were examined by Colonel Bingham, who kindly 
informs me that ‘the specimens were unfortunately in frag- 
ments, but, as well as I could make out, they belong to the 
genus Dolichoderus, and are probably D. bituberculatus, Mayr, 
which is spread from India to New Guinea.” In the pitcher of 
D. pectenoides fragments of ants were present which Colonel 
Bingham identifies as probably a species of Aphenogaster, a 
genus numerously represented in the Indo-Malayan region. A 
large number of ant-pupz were also found in the same pitcher Tf. 
The pitchers of D. complex and of Haviland’s Bornean specimen 
were well supplied with soil, but contained nothing that I could 
recognize as ant-remains. But it is needless to point out that 
the absence of insect-remains from dried plants proves nothing 
except that the insects, if present when the plant was collected, 
took an early opportunity of leaving. 
We have, then, four species bearing pitchers into which soil 
cannot find its way by the action of gravity. Soil is, however, 
present in marked quantity. Itis also proved that ants frequent 
the pitchers and make their nests in them. There is no evidence 
of any other means by which solid matters can find their way in. 
The conclusions on these grounds seem to be perfectly justitiable 
(1) that the “soil” in the pitchers is brought in by ants as 
* A carnivorous function has been suggested for the pitchers of D. Rafflesiana 
(Delpino, Nuovo Giorn. Bot. Italiano, vol. iii. pp. 174-6, and Malpighia, 
vol. iv. pp. 13-17), and, although there are now no grounds for believing this to be 
the case, it was not, on the face of it, absurd to suppose that the inner pitcher 
might serve such a purpose. I therefore submitted these ants to careful 
microscopic examination, but their remains showed no signs of having under- 
gone anything of the nature of a digestive process. 
+ Dr. Forel figures a “ paste-board” nest of Dolichoderus bituberculatus from 
Bangkok. At the same time he states that ‘the chief feature of ant 
architecture is its irregularity.” Judging from the details given of the various 
forms of nest adopted under different conditions by the same species, there 
would be nothing surprising in the fact that this species should nest in two 
such different places as a paste-board structure on the bough of a tree and the 
cavity of a Dischidia-pitcher. Species of Aphenogaster are stated to use earth 
es *netinermaterial (Forel, Smithsonian Report, 1894, pp. 480-490, pl. Ivi. 
ig. 15. 
