134 PLANTS WITH TRAPS AND PITFALLS TO ENSNARE ANIMALS. 
what appears to be the lid of the pitcher is the lamina, as it is in Cephalotus and 
the Sarracenias. In this case also the lamina seems to be but little developed in 
comparison with the wonderfully metamorphosed petiole. In the majority of the 
species of Nepenthes, the mature pitchers are from 10 em. to 15 em. in height. In 
the graceful Nepenthes ampullaria they are only from 4 cm. to 6 em. high; but, 
on the other hand, in the species indigenous to the primeval forests of Borneo they 
reach a height of 30 cm. or even more. The pitchers of Nepenthes Rajah have a 
height of 50 cm., and their orifices are 10 cm. in diameter, whilst below the orifice 
they expand to 16 cm.; so that if a pigeon were to fly into a pitcher of this kind 
it would be completely hidden in it. Immature pitchers are still closed by their 
covers. Often they are hairy outside; and, according to the colour and lustre of 
the hairs, they may be rusty in tone or glittering like gold; not rarely they look as 
if they were powdered with flour (e.g. N. albo-marginata), and sometimes are even 
snow-white. Subsequently the lid is raised, and the downy coat disappears either 
partially or entirely. Having thus become glabrous, the pitchers display a yellowish- 
green ground colour, for the most part flecked and veined with purple; and many 
are of a bluish, violet, or rose tint near the orifice, or dark-red as though saturated 
with blood. The lid is similarly gaily coloured; and the variety of the tints is 
increased by the fact that a pale-blue zone is visible in the interior, beneath the 
swollen involute rim of the opening, which is itself brownish, yellowish, or orange- 
red. Gaily-coloured pitchers of this kind look at a distance just like flowers, 
and remind one, in particular, of the most brilliant floral forms of the liane-like 
Aristolochias indigenous to tropical forests. This fact is the more noteworthy, 
because the genus Nepenthes is closely allied to the genus Aristolochia in respect 
of systematic relations. 
The bright pitchers of Nepenthes, visible from afar, are sought, just as flowers 
are, by insects, and probably by other winged creatures as well; and this occurs all 
the more because there is a copious secretion of honey by the epidermal cells upon 
the under surface of the lid, and on the rim round the mouth of each pitcher. The 
swollen and often delicately-fluted rim, in particular, drips and glitters with the 
sugary juice; and it would be permissible in this connection to speak of a honeyed 
mouth and sweet lips in the most literal sense of the words. Animals which suck 
honey from the lips of Nepenthes pitchers wander, as they do so, only too readily 
upon the interior surface of the orifice. But the inner face is smooth and precipitous, 
and rendered so slippery by a bluish coating of wax that not a few of the alighted 
guests slip down to the bottom of the pitcher and fall into the liquid there 
collected. Many of them perish in a short time; others try to save themselves by 
climbing up the internal face of the pitcher, but they always slip again on the 
polished, wax-coated zone, and tumble back once more to the bottom. In large 
pitchers the involute rim of the aperture is in addition armed with sharp 
teeth, which are pointed downwards and bristle in front of such of the unlucky 
victims in the pitfall as try to emerge (see fig. 19°). In a number of species 
(N. Rafflesiana, N. echinostoma, N. Rajah, N. Edwardsiana, and N. Veitchii, all 
