439 
Insectivorous Plants ( Part //). 
ventilators are open in the Sarracenia- and Nepenthes-houses, 
they pass into the former, but seem to avoid the latter. It may 
be a question of relative heat with the insects, but the matter can 
only be satisfactorily settled by examination of pitchers in 
their native haunts, or of the contents of such if carefully trans- 
ported to this country. 
The number of insects caught is frequently very great, and 
some species seem to excel in this : N. Hookeri, N. Rafflesiana , 
N. albo-marginata , N. khasyana , and N. Phyllamphora are 
the finest catchers; N. gracilis, N . sanguine a, N . Teysmanniana , 
and N. distillatoria are indifferent ; while N. ampullaria is 
bad. I give this only as my experience in plant-houses, but 
when wild the results may be different, though I do not think 
widely so. That the presence of insects in the cavities either 
by sight or odour helps to attract others has often occurred 
to me as being an aid to the honeyed bait. That they draw 
the higher animals is undoubted, and I may here notice the 
ingenious and likely hypothesis which Mr. Burbidge has 
proposed to account for the two spurs of N. bicalcarata. 
The rodent Tarsius , in the region where the plant grows, 
frequents various Nepenthes to rifle the pitchers of their insect 
earnings by bending down and shovelling out the contents. 
It has learned, from being caught in the nape of the neck by 
the two spurs, to shun the species named. Four seasons ago, 
a rather small pitcher of N. Hookeri caught within a fortnight 
seventy-three cockroaches, large and small, having been 
emptied out on three occasions. The odour resulting from 
digestive decomposition would undoubtedly tempt those 
succeeding the first few caught. My experiments have not 
been extended enough to enable me as yet to advance our 
knowledge of the digestive action carried on in the pitchers, 
but I hope to publish on this at a later period. 
I can scarcely leave this part of my paper without referring 
to the remarkable relation which N. bicalcarata has to an ant 
that frequents it, as described by Mr. Burbidge. The matter 
completely puzzled me, till that gentleman kindly gave me 
his simple but original explanation. In seven out of every 
