Chap. XII.] 
BUTTERFLIES. 
425 
waterfalls, living mainly in the shade of the moist 
foliage, and returning to it in haste after the shortest 
nights, as if their slender bodies were speedily dried up 
and exhausted by exposure to the intense heat. 
Among the largest and most gaudy of the Ceylon 
Lepidoptera is the great black and yellow butterfly 
(Omithoptera darsius, Gray) ; the upper wings of 
which measure six inches across, and are of deep velvet 
black, the lower ornamented by large particles of satiny 
yellow, through which the sunlight passes. Few insects 
can compare with it in beauty, as it hovers over the 
flowers of the heliotrope, which furnish the favourite 
food of the perfect fly, although the caterpillar feeds on 
the aristolochia and the betel leaf, and suspends its 
chrysalis from its drooping tendrils. 
Next in size as to expanse of wing, though often 
exceeding it in breadth, is the black and blue Papilio 
Polymnestor, which darts rapidly through the air, 
alighting on the ruddy flowers of the hibiscus, or the 
dark green foliage of the citrus, on which it deposits 
its eggs. The larvae of this species are green with 
white bands, and have a hump on the fourth or fifth 
segment. From this hump the caterpillar, on being 
irritated, protrudes a singular horn of an orange colour, 
bifurcate at the extremity, and covered with a pungent 
mucilaginous secretion. This is evidently intended as 
a weapon of defence against the attack of the ichneumon 
flies, that deposit their eggs in its soft body, for when 
the grub is pricked, either by the ovipositor of the 
ichneumon, or by any other sharp instrument, the horn 
is at once protruded, and struck upon the offending 
object with unerring aim. 
Amongst the more common of the larger butterflies 
