CHAP. XXI.] 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 Euryarthrum, Leprodcra, Aris- 

 tobia, Coelosterna, and Entelopes, 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, Sphingnotus, Arrhenotus, Tmesisternus (the last three 

 genera abounding from New Guinea to Celebes, but totally 

 unknown further west), Hestima, Trigonoptera, AmUymmxi, 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, Clytns, appears to be cosmopolitan. Saperda and CalUchro- 

 ma aie the only others that perhaps occur in every region ; but 

 these are both wanting over wide tracts of the earth's surface, 

 Sap)erda 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 ; Ceratopliorus has 2 species in West Africa and 1 in New 

 Zealand. Xystrocera is mostly African, but has single species in 



