OF THE MALAYAN REGION. 3 
Edward Doubleday, in his * Genera of Diurnal Lepidoptera, says, “ The Papilionidæ 
may be known by the apparently four-branched median nervule and the spur on the 
anterior tibiæ, characters found in no other family.” The four-branched median nervule 
is a character so constant, so peeuliar, and so well marked, as to enable a person to tell, 
at a glance at the wings only of a butterfly, whether it does or does not belong to this 
family ; and I am not aware that any other group of Butterflies, at all comparable to this 
in extent and modifications of form, possesses a character in its neuration to which the 
same degree of certainty can be attached. The spur on the anterior tibie is also found 
in some of the Hesperidæ, and is therefore supposed to show a direct affinity between the 
two groups; but I do not imagine it can counterbalance the differences in neuration and 
in every other part of their organization. The most characteristic feature of the Papi- 
lionidæ, however, and that on which I think insufficient stress has been laid, is undoubt- 
edly the peculiar structure of the larvæ. These all possess an extraordinary organ 
situated on the neck, the well-known Y-shaped tentacle, which is entirely concealed in a 
state of repose, but which is capable of being suddenly thrown out by the inseet when 
alarmed. When we consider this singular apparatus, which in some species is nearly 
half an inch long, the arrangement of muscles for its protrusion and retraetion, its per- 
fect concealment during repose, its blood-red colour, and the suddenness with which it 
can be thrown out, we must, I think, be led to the conclusion that it serves as a protec- 
tion to the larva by startling and frightening away some enemy when about to seize 
it, and is thus one of the causes which has led to the wide extension and maintained 
the. permanence of this now dominant group. Those who believe that such peculiar 
structures ean only have arisen by very minute successive variations, each one advan- 
tageous to its possessor, must see, in the possession of such an organ by one group, and 
its complete absence in every other, à proof of a very ancient origin and of very long- 
continued modification. And such a positive structural addition to the organization of 
the family, subserving an important function, seems to me alone sufficient to warrant us 
in considering the Papilionidæ as the most highly developed portion of the whole order, 
and thus in retaining it in the position which the' size, strength, beauty, and general 
structure of the perfect insects have been generally thought to deserve. 
The Papilionidæ are pretty widely distributed over the earth, but are especially abun- 
dant in the tropies, where they attain their maximum of size and beauty and the greatest 
variety of form and colouring. South America, North India, and the Malay Islands are 
the regions where these fine insects occur in the greatest profusion, and where they 
actually become a not unimportant feature in the scenery. In the Malay Islands in par- 
ticular the giant Ornithopteræ may be frequently seen about the borders of the cultivated 
and forest districts, their large size, stately flight, and gorgeous eolouring rendering them 
even more conspicuous than the generality of birds. In the shady suburbs of the town 
of Malacca two large and handsome Papilios (Memnon and Nephelus) are not uncommon, 
flapping with irregular flight along the roadway, or, in the early morning, expanding 
their wings to the invigorating rays of the sun. In Amboyna and other towns of the 
Moluceas, the magnificent Deiphobus and Severus, and occasionally even the azure-winged 
Ulysses, frequent similar situations, fluttering about the orange-trees and flower-beds, or 
B 2 
