of Europe would be to him southerners quite irrespective of
their original home, which might be in Southern Europe, Asia, or Africa.

The Swallow-tail is well known to all collectors of Butterflies in
England, though it has of late years become very rare and is now
confined to a few localities in the east of England. The members of the
family _Papilionidae_, to which it belongs, are mostly large and striking
species, and their distribution is therefore more accurately known than
that of the smaller and less conspicuous butterflies. Only four
different kinds of Swallow-tail Butterflies inhabit Europe, but in
Southern Asia and the Malay peninsula they attain their maximum as
regards numbers; and there we find a great many species of this genus
_Papilio_. Of the four European species only one, viz., _Papilio
hospiton_, is peculiar to Europe; all the others range into Asia. It
would seem, therefore, as if this genus was an Asiatic one and had
migrated to Europe, and that the route taken was the one from Asia Minor
across to Greece. We have a similar case in the closely allied genus
_Thais_ two of the three European species living also in Asia Minor.
_Thais cerisyi_ inhabits some of the Greek islands, as well as the
mainland of Turkey and Greece.

Another genus of the great family _Papilionidae_ with which most
lepidopterists are well acquainted is _Parnassius_. What
butterfly-hunter has been in Switzerland without hearing of, or seeing,
the famous _Parnassius Apollo_? We have four European species of
_Parnassius_, only one of which is peculiar to our continent, but the
locality where it occurs, the Caucasus, is on the borders of Asia.
Almost all the other species are Asiatic, none however range to the
south. Its headquarters, and I think its original home, are the
mountains of Central Asia. From there it has spread--some species to
the Himalayas, and a few to Europe and North America. But these
migrations are not of very recent date. _Parnassius_ no doubt arrived
accompanied by a large number of other Central Asiatic mountain insects
and plants. I shall refer to the latter again when dealing with the
origin of the Alpine fauna, but meanwhile it might be mentioned that the
famous Swiss "Edelweiss" (_Leontopodium alpinum_), which we are
accustomed to regard as a typical Alpine plant, is certainly of Asiatic
origin. In some parts of Southern Siberia it is one of the common
meadow-flowers, and ranges from there south into Kas