PAPILIO. 
93 
spines at the apex, and the claws undivided : hinder 
wings scolloped, and furnished with a long narrow 
projecting lobe like a tail ; their interior edge con- 
cave or grooved, to receive the abdomen. The ca- 
terpillars are smooth and naked, and often ornament- 
ed with very beautiful colours. They have the power 
of protruding from the neck a soft fleshy horn, which 
divides near the middle into two branches, like the 
letter Y. This appendage might be supposed to 
serve the same end as the horns of the snail, to which 
it bears much resemblance, but, unlike that animal, 
the caterpillars are said to push it forth only when 
alarmed, and it has therefore been regarded as a 
means of defence, the more especially since it dif- 
fuses a penetrating and disagreeable odour. The 
caterpillar of P. Machaon, with the horns exserted, 
is represented on Plate III. fig. 1. 
The chrysalis is angular, and fixed by a silken 
band round the middle. 
These insects composed the section which Lin- 
naeus distinguished by the name of Equites. Nearly 
200 species have been described, many of which are 
the largest papilionaceous insects known, and re- 
markable for the variety and richness of their colours. 
They abound in the tropical regions of both hemi- 
spheres, but occur very sparingly in temperate cli- 
mates. Besides the two which we have figured, only 
one other species is known to inhabit Europe, viz. 
P. Alexanor, which, though observed of late years 
more frequently than formerly, is still extremely rare. 
