PAPILIONm^. 
193 
spine-like tubercular processes ; second (prothoracic) segment containing 
dorsally an exsertible forked glandular fleshy organ, emitting a pene- 
trating odour. 
Pupa. — Very variable in shape, but usually more or less curved or 
bent backward superiorly, and angulated ; head usually more or less 
bifid, but sometimes sub-truncate, blunt, or rounded ; back of abdomen 
often tuberculated. 
This Sub-Family is very distinct from the Pierince, the approach 
made to the latter by the aberrant Parnassius ^ being very slight, and 
such genera of Piermcc as Mesaina, Gray, Pavidma, Oberth., and Sti/^v, 
Staud., not exhibiting any structural af&nity, but only a superficial 
resemblance to Parnassius,^ The salient features in the Papilionina^ 
are, as regards the perfect insects, the arrangement of the disco-cellu- 
lar and radial nervules of the fore-wings, making the lower radial appa- 
rently a fourth median nervule ; the development of the interno-median 
rervule and of the free internal nervure in the same wings; and in 
the hind wings the hollowed inner-margin (with absence of the internal 
nervure), and formation of a small prediscoidal cell by the branched 
precostal nervure ; while the first pair of tibiae bear on their inner edge 
a conspicuous process or spur. The caterpillars stand alone among 
those of the entire Sub-Order ^ in possessing the strongly scented 
exsertible fleshy organ or " tentacle " in the neck, which is instantane- 
ously protruded and directed vibratingly towards any part where the 
insect may be touched. This organ is usually of some red or crimson 
tint, but sometimes blue or yellow ; and its sudden appearance, mena- 
cing motion, and penetrating disagreeable odour, combine to make its 
possessors alarming and repulsive to their foes. 
Papilio, with some 400 species, is beyond comparison the domi- 
nant genus of the Sub-Family, extending throughout the globe, but 
very poorly represented in the Palasarctic, Nearctic, and Australian 
Piegions. The other twelve genera, including Ornithoptci^a (about 
twenty species), together muster only sixty-one species, and of these 
Parnassius alone counts twenty-three, five of the genera being mono- 
typic. In curious contrast to its poverty in species of Papilio is the 
richness of the Palaearctic Eegion in generic forms, Sericinus, Thais, 
Ilypermnestra, Doritis, and Luehdorfia being all peculiar to it, and 
Parnassius peculiar except for two or three North- American forms ; 
^ See Doubleday, Gen. Diurn. Lep., i. p. I (1846). The singular Tui'kestan genns 
Sypermnedra, however, has in outline and hind-marginal markings of the wings, and espe- 
cially the pattern and colouring of the under side of the hind-wings, a striking resemblance 
to Anthocharis and the Daplidice group of Pieris. 
^ It is worth mention, however, that the chrysalis of Zegris (a Southern Palaearctic 
genus close to Anthocharis) is enclosed in a delicate silken web after the manner of that of 
Parnassius. 
^ The whole Order Lepidoptera is known to yield only one other genus, viz., Dicranura 
{Cerura) among the Bombyces, whose larvee have an equally developed organ of this re- 
markable description ; and in these the organ is double instead of merely forked, enclosed 
in special sheaths, and occupies the posterior instead of the anterior end of the body. 
VOL. nr. ]sf 
