CHAP. XXI.] 
INSECTS. 
485 
sub-region which never cross the narrow seas to the east of 
them ; 6 others which only pass to Celebes ; and 2 more which 
have extended from Java along the closely connected line of 
islands eastwards to Timor. On the other side, we find 5 strictly 
Austro-Malayan genera, and 2 others which have a single re- 
presentative in Java. The following is a list of these genera : — 
Indo-Malayan Genera : — Amathusia , Thaumantis, Tancccia, 
Eurytela, Her da, Zemeros, Taxila , Aphneus, Prioneris , Pereas , 
Glerome, Adolias, Apatura, Limenitis, Iolaus , Leptocircus, (the 
last six reach Celebes) ; Piscophora, Thestias ; (the last two reach 
Timor.) 
Austro-Malayan Genera: — Ilamaclryas, Jlypocista, Mynes , 
Picallancura, Elodina , Hyades, Prothoe (the last two reach 
Java). 
The most characteristic groups, which range over the whole 
Archipelago and give it a homogeneous character, are the various 
genera of Dan aid the genus Elymnias, and Amblypodia with a 
few other Lycaenidse. These are all abundant and conspicuous 
groups, but they are nevertheless exceptions to the general rule 
of limitation to one or other of the regions. The cause of this 
phenomenon is probably to be found in the limitation of the larvae 
of many Lepidoptera to definite species, genera, and families of 
plants ; and we shall perhaps find, when the subject is carefully 
investigated, that the groups which range over the whole Archi- 
pelago feed on genera of plants which have an equally wide range, 
while those which are limited to one region or the other, have food- 
plants belonging to genera which are similarly limited. If is 
known that the vegetation of the two regions differs largely in a 
botanical sense, although its general aspect is almost identical ; 
and this may be the reason why the proportion of wide-ranging 
genera is greater among such insects as feed upon dead wood, 
than among those which derive their support from the juices of 
the living foliage. This subject will be again discussed under 
the various families of Coleoptera, and it will be well to bear in 
mind the striking facts of generic limitation which have been 
here brought forward. 
