( cii ) 



geograjihii-al barriers hofoim' iiit'lVoi'tive, aiiil the influence of isolixtioii (segrega- 

 tion) is annulled. The wiunlering Hawk Moths, like Ackeraniin (itiopos, llerse 

 concolriiU and eiiKjuldht, lliiijiotion irlm'o and osiri.'^, Deilepliila ncrii, Tlifretra 

 7iessus, etc., do not vary geograpiiically, or only in a slight, degree. However, 

 considering what we liave said about tlie ])Ower of flight' and isolation, it 

 cannot be wondend at tliat a good many species of swift-flying genera have 

 doveloiied into genv'raiihieiil varieties (= subspecies) in spite of their power 

 of flight. Notwithstanding this fact, in the Sjtiiingidae the rule holds good 

 that, 1^)1 till' ifliolf, the sluggish species are more often and more distinctly 

 varialile geographieally than the swift-fliers, and that, further, the areas of 

 the geographical races of slow-flyers are mostly smaller than those of the 

 subspecies of less sluggisli Hawk Moths, as exemplified by Ambitlirimte and 

 ( 'lioerocaiiipinae. 



There is only one cosmopolitan Sphingid, Celerio lineata ; it consists of 

 three subspecies, one inhabiting the Western Hemispliere and two the Eastern. 

 Ilerse concolvtdi and Ili/jpotioii^ celerio oecniiy jii'actically tlie whole Old World, 

 while Heme ciiii/ulata and Protoparce sextn occur from Canada to Patagonia. 

 One species {Celerio gallii) is common to the Nearctic and Palaearctic Regions. 

 Cephonodes liijlus is found, in three subspecies, from Sierra Leone to Mada- 

 gascar and eastwards to Australia, with a wide gap in the Malay Archipelago. 

 Deilepliila nerii inhabits the whole Aethiopian Region, and extends far into 

 Europe and soiitli-eastward.s into Western India and Ceylon. A number of 

 species occur all over (he Aethojiian Region witliont being split up into 

 subspecies {Ilippotion cson : lii(siotliia medea : ( 'oelonia fulcinotata : etc.) ; 

 others are of wide distrilnition in the Palaearctic or Oriental Regions (Macro- 

 gloit.tum slellutinum ; llippotioii l)Ot'rliaciue, velo.v ; Theretra nesstis ; ('e/jlioiwdes 

 picas: etc.); and others again occur all over the Neotropical Region or go 

 even far intu llic nortliern lialf (if the New World ( Xi/lopli(ine.s fersa, plitto : 

 Pseidlospliiii-r tetrio : Krinni/is atope ; I'lpixtor laijiihria : etc.). The disti-ibntion 

 of such common species is very instructive in one resjiect. Although their 

 range is wide, it is nevertlieless restrictfd, and we ask ourselves. What 

 antagonistic factors are there i)reventing these Sphimpdne from occupying the 

 whole globe 'i 



A country must be accessible to a species. If there is a practically 

 unsurmountable jihjsiograjiliical barrier, the species have little chance of passing 

 over it. The swift-flying Sphingidue are not able to cross the Atlantic and 

 Pacific Oceans, none of the New and Old World species being identical, not 

 even Celerio lineata and gallii being the same in the AVestern and Eastern 

 Hemisphrrcs ; and the Indian Ocean is an equally effective barrier. But there 

 is no such barrier to prevent Maeroglmsiim. sfellatartiiii, which ranges from 

 Morocco and Ireland to Japan and North AVest India, from going farther south 

 and east in India ; no physiographieal cliasm faces in .Spain the Aethiopian 

 Jlippotioh oxiris, which extends from Madagascar to the Pyrenean Peninsula ; 

 no geographical barrier keejis the African Deilephila nerii back from settling 



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