( cxxxiv ) 



cosmopolitan ones (//rrsc ami Cclrn'o). The affinity which there exists between 

 the Neotrojiical anil Aethiopian Regions is shared by India. 



Since low types of all the subfamilies of Sjihingidae, with the exception of 

 the Sesiinae, occnr in the trojncs of the 'Western and Eastern Hemisjiheres, there 

 is indeed a close affinity in this respect between the tropics of the Old and 

 New Worlds. But the affinity constitnted by the presence of allied low types has 

 (juite a dift'ereut bearing on (Hiestious of geographical distribntiou from that affinity 

 which is established by the occurrence of closely related specialised genera and 

 species. Let us take, for instance, the AclieroHtiinue and AmhitUcinae. The 

 lowest African, Indian, and American geneia Xantlwpan, Meganoton, Cocytius, 

 iind I'lotojxinr are as nearly related to each other as the younger derivatives 

 ll;/loi<ui', (')'ratomia, Tluuimocclia, etc. : and the generalised Ambulicine genera 

 I'ro/(imbid>/j-, Am//li/jjten(s, Compsogenc, and Uxi/ambuli/x are phylogenetically as 

 closely connected as are the specialised genera Sjj/iiiu-, Amorjj/ca, Faclii/ sphinx, 

 I'lii/llosphiiu/ia, Crcssoiiia, etc. The migration northwards and westwards into 

 the Nearctic Eegion of the derivations from the ancestral Oriental Ambulicinac, 

 represented by Amplypterus in the present epoch, and the extension of the 

 derivations from the lowest Neotropical AcherOHtiinae, Protoparce, or an extinct 

 genus similar fo it, north and eastward into the Palaearctic Region as far south 

 as the Himalayas, and, further, the modification of either branch into a number 

 of genera, have required a long time. (Since not one of the younger derivations 

 from the Oriental Ambaliciiiac and African Ackerontiiiiao occurs in South 

 America, and none of the younger developments of the Neotropical branches of 

 these subfamilies are found in Africa or India, though the younger developments 

 have become distributed northward as widely as .stated above, it is obvious that 

 there was no direct connection between the Neotropical Region and Africa and 

 India during that period in which the evolution and distribution of the younger 

 members of the two snbfaniilies took place. That is to say, the time which 

 has e]a]ised, since the African Xdiithopan and the Neotropical Coci/tius, or the 

 Indian ('onipsoyene and the Neotropical Amplifpterus, closely allied though thej- 

 are, became geographically separated, is more remote than that which elapsed 

 since the Nearctic and Palaearctic Regions exchanged a number of specialised 

 genera. The distribution of the other subfixmilies confirms this conclusion. The 

 generalised Sf.siimie occnr only in the Neotropical Region, not one species being 

 peculiar to any other region, though one single sjiecialised— the most highly 

 sjiecialised— branch has crossed to the Palaearctic Region, and established itself 

 ill two genera in the tvojiics of the Old World (Safaspes, Cephomdes). The 

 oldest genus of i'liilumpdinae is again Neotropical (I'koliis). It is sharjily 

 sejiarated from the rest of the subfamily, and the only one occurring in the 

 Neotropical Region, besides a derivative from Pholus found on the Sandwich 

 Islands ('nimstuiuii). All the other Philaiiipelimie are of t)ld \\\n-\A extraction, 

 and have partly migrated from the Eastern Heniisjiiiere into the Nearctic 

 Region. In both the Sesiimw and I'hilnmpdinae the geograjihical barrier 

 between the Eastern and Western tropics must have been elfective at a very 



