CHAP. XXl.j 
INSECTS. 
'501 
sub-regions. Many of these, it is true, consist of single species 
confined to a single island, and we will not lay any stress on 
these ; but there are also several important groups, which extend 
over the Indo-Malay or the Austro-Malay islands only, stopping 
abruptly at the dividing-line between them. For example, on 
the Indo-Malay side we have Euryarlhrum, Leprodera, Aris- 
tobia , Coelosterna, and Entelopcs , and what is perhaps even more 
satisfactory, the large genera Agelasta and Astathes, abundant in 
all the Indo-Malay islands, but having only one or two species 
just passing the boundary into Celebes. On the other side we have 
Tethionea, Bphingnotm, Arrhenotus, Tmesisternus (the last three 
genera abounding from New Guinea to Celebes, but totally 
unknown further west), Hestima , TrigonopUra, Amhlymora , Ste- 
silea, Enes, and the large genus Micracautha , with but a single 
species beyond the boundary,— 30 Austro-Malayan genera in all, 
each found in more than one island, but none of them extending 
west of Celebes. Here we have clear proof that the boundary 
line between the two great regions exists for Longicorns, as well 
as for all other animals ; but in this case an unusually large 
number have been able to get across it. This, however, does not 
abolish the barrier, but only proves that it is not absolutely effect- 
ual in all cases. Those who maintain that the Malay Archi- 
pelago forms a single Coleopterous region, must disprove or 
explain the instances of limited range here adduced. 
Out of nearly 1500 known genera of these insects, only one 
genus, Clytus, appears to be cosmopolitan. Sctpcvda and Callichro- 
ma are the only others that perhaps occur in every region ; but 
these are both wanting over wide tracts of the earth’s surface, 
Baperda being absent from Tropical Africa and the Malay Archi- 
pelago ; and Callichroma from the Australian region, except one 
species in Polynesia. Many of the genera of Longicorns have a 
somewhat wide and scattered distribution, indicative of decadence . 
or great antiquity. Mallodon and Parandra are mostly South 
American, but have species in Australia and Africa ; Oeme is 
found in Brazil and the United States, with one species in West 
Africa; Ceratophorus has 2 species in West Africa and 1 in New 
Zealand. Xystrocera is mostly African, but has single species in 
