( t-vi ) 



TIu' (liliiTi'iict's ill tlic number of species between the three tropical He^ions 

 are not considerable, tlie Neotropical Region possessing altogether 236, the 

 Aetliiopian 170 (many new ones will be discovered), and the Oriental 2.")0. The 

 Palaearctic and Nearctic Regions iiave each 75 species. 



The differences in the distribntion of the species of the five subfamilies 

 into which the Sphiinjiiha' fall in our classification are remarkable. The 

 Aclierontiinae and Sesiinae are for the greater part American, while the 

 Ambulicinae, Philnmpelinae, and Choerocam.pinae have more representatives in 

 the Old than in the New World. The difference is especially large in the case 

 of the Sesiinae on the one hand, and Amltitlirinae and Plulumpi'Unae ou the 

 other. The projiortion between western and eastern species of Acherontunae 

 (84 : 52) is almost exactly reversed in the Clioerocampinae (56 : 86). The 

 Ambulicinae are most numerous in Africa, nearly half of the Philampelinae are 

 Oriental, and about one-third of them Aethiopian, while the Neotropical Region 

 has scarcely one-twelfth of the total. North America has no single species of 

 Choerocampinae of its own, but Central and South America possess more species 

 than auy other single Region. The number of species of Ac/ierontii»ae is much 

 larger in the Neotropical Region than anywiiere else. 



However, the numbers of species which inhabit a country in themselves 

 cannot be trusted when forming an opinion on the diversity of its fauna. 

 Comparing, for instance, the number of Clioerocampinae peculiar to the Neo- 

 tropical Region with the number of purely Palaearctic species (48), it would 

 appear from these figures alone that the Palaearctic Sphingid fauna was not 

 more diversely developed than the Clioerocampinae of South and Central 

 America ; whereas, in fact, these Neotroi)ical Sphingids belong to only three 

 allied genera, i.e. are very homogeneous, and the Palaearctic species to more than 

 twenty genera of five subfamilies. The diversity in tiie development of a family 

 is better illustrated by the genera of the country, since a genus is a category 

 higher than species, rejiresenting as it were the generalised state of development 

 of wiiich tlie various congeneric species are modifications. Each Region has one or 

 more genera ci ntaining a large number of species, while the nearest allied genera 

 comprise as a rule few or single species. Protoparce, Krinni/is, and Xi/lophanes 

 are large Neotropical genera ; Uijloici(» has nnmerous species in North America, 

 Celerio in the western half of the Palaearctic Region, Macroglossum and Tlieretra 

 in the Oriental Region, and Poli/pfi/clnis in Africa. Such genera and the com- 

 monly occurring species give a' country its special feature from the point of view 

 of a collector, while the number of genera and their diversity are the more 

 important feature for the classifier and for the student of the origin of the fauna, 

 relying as they both do principally upon the affinities presented l)y the genera. 



We have grouped the 770 species of Spkingidae in 167 genera, of which 

 the table here following gives the numerical distribution. Since genera are 

 groups of species, and hence generally of wider distribution than single species, 

 the number of genera common to adjacent Regions is proportionally very much 

 larger than the number of species common to them. 



