( cvi ) 



The iliftereiices in tlie number of species between the three tropical Regions 

 are not considerable, the Neotropical Regiou possessing altogether 236, the 

 Aethioiiiiui ITO (many new ones will be discovered), and the Oriental 250. The 

 I'alaearetic and Noarctie Regions liave each 75 species. 



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

 into which the Spldiii/iddr fall in our classification are remarkable. The 

 AclieroiitiinaL' and Si'Ktimit: are for tlie greater part American, wliile the 

 Ambulicinae, PI(il<tiii/icliiHu', and Cliocrocumpinac have more representatives in 

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

 of the Si'siiiiae on the one hand, and AmbuUciiiae and Pldlampelinae on the 

 other. The proportion between western and eastern species of Acherontiinae 

 (84 : 52) is almost exactly reversed in the Choerocampinae (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 any other single Region. The number of species of Acherontiinae is much 

 larger in the Neotropical Region than anywhere else. 



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

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

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

 tropical Region with tlie number of jiurely Palaearctic species (48), it would 

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

 more diversely developed than tlie Choerocampinae of Sonth and Central 

 America ; whereas, in fact, these Neotrojjical Sjihingids belong to only three 

 allied genera, i.e. arc very liomogeneous, and the Palaearctic species to more than 

 twenty genera of five snbfixmilies. The diversity in the development of a family 

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

 higher than species, re])resentiMg as it were the generalised state of development 

 of which the varions congeneric species are modifications. Each Region has one or 

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

 comprise as a rule few or single si)ecies. Frotoparce, Erinnyis, and Xiilophanea 

 are large Neotropical genera ; Ili/Ioiciix has numerous species in North America, 

 Celerio in the western lialf of tlie Palaearctic Region, Macroglossum and Theretra 

 in the Oriental Region, and Poli/pti/chux in Africa. Such genera and the com- 

 monly occuri'ing s]iccies give a country its special feature from the point of view 

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

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

 relying as they both do principally upon the affinities presented by the genera. 



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

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

 gronps of species, and lience 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 comuKJii to them. 



