( civ ) 



while the true cause of the absence or scarcity of those insects in the Malay 

 Archipelago is probably of i|uitc a (liflerent kind, as we shall see later on. 

 The North American Spln-cudiita ahhotii is confined to the Atlantic side of the 

 Continent ; tiic only other species of tlie genus (tiie only near ally, in fact, of 

 abbotti) is restricted to the Pacific side of Asia (Aiuurland, (Jhina). Tiie Indian 

 genera Ajjocali/iisis and I'soidoifolbiiia stand quite isolated in the Old World, 

 their nearest (and very close ally) being the Neotropical Euri/glottis. The 

 South African genus Rkodafra comes nearest to the Palaearctic Perf/efia. If we 

 compare such cases with tlie distribution of Cclcn'o, of which one species is 

 cosmoi)olitan, one Holarctic, several Palaearctic, and one each Malagassic, Argen- 

 tinian, Chilian, and Cuban, while two are confined to the Sandwich Islands, it 

 becomes obvious that the interrupted range of genera or allied genera is the 

 result of the extinction of the insects (or allied species) in the now non-inhabited 

 intermediate districts rather than the result of great geographical changes. We 

 have to do here with the remnants of once more uniformly distributed gronp.«, 

 remnants existing where by chance tlie conditions were favourable for their 

 preservation. However, it is not our intention to speculate on the aj)parently 

 abnormal distribntion of single species and genera, fascinating as it is, but to 

 lay before the reader a short summary of the actual stale of the distribntion 

 of the ISjiIiingidae, from which he will better understand the comfiosition of 

 the Sphitigid fauna ot the varions areas tiian from a speculative elncidation of 

 single cases. Accepting the Wallacean division of the globe into five Regions, 

 we have a distribntion of the 770 species of Hawk Moths, as illnstrated in the 

 table on the op{)osite page. 



There are only 2 species common to the VV'estern and Eastern Hemispheres, 

 each represented in America by 1, and in the Old World one by 2 and the 

 other by 1 subspecies. Of the remaining 768 species, as yet known, 293 are 

 ]>ecnliar to the New AV'orld, inclnding the Sandwich Islands (3 species), and 47;") 

 to the Eastern Hemisphere. Since the Papuan Snbregion and Africa luirbonr 

 without doubt a great many undiscovered species, i)ro])ortionally more than Soutii 

 and Central America, we can estimate the proportion of the species inhabiting the 

 New and Old Worlds as being 1 : 2, or presumably 32U-odd to 650-odd. The 

 superiority of the East over the West of the globe in the number of species of 

 Hawk Moths is quite intelligible, since tropical America is far smaller than 

 the tropics of the Eastern Heniispiiere, does not offer so mnch variety in the 

 conditions of life, and is not so broken physiographically. A heteromorphic 

 country has a heteromorphic fauna. 



The paucity of the SpJiiiu/idae in the temperate Regions is very apparent 

 in the table. North America, Europe, North and Central Asia, and Palaearctic 

 Japan, where few new species will be discovered, if any, jwssess only 100-odd 

 species peculiar to them, as compared with 620-odd peculiar to the only 

 partially explored tropical and subtropical countries. New discoveries will alter 

 ttie ])roporti(ni so much to the disadvantage of the northern temperate Regions 

 that the proportion will ultimately bo about 1 : 9, according to our calculations. 



