64 



THE YOUNG NATURALIST. 



acterize a region positively, but we must also consider the absence of many 

 important groups of the Oriental, Ethiopian and Arctic region; and we shall 

 then find, that taking positive and negative characters together, and making 

 some allowance for the necessary poverty of a temperate as compared, with a 

 tropical region, the Palsearctio is almost as strongly marked and well defined 

 as any other." 



Dr. Staudinger has prepared a list of the Lepidoptera inhabiting tf the 

 territory of the European Fauna," and it is an evidence of the correctness of 

 the conclusions of Wallace, that from entirely different data, Dr. Staudinger 

 has defined so nearly the same area, that for all practical purposes it may be 

 considered identical. Dr. Staudinger first takes the Lepidoptera of Europe 

 proper — Geographical Europe. Then wherever he finds the Lepidoptera 

 occurring in Europe to be at least 60 per cent of the whole, he includes the 

 locality where such proportion obtains, as one inhabited by the Fauna of 

 Europe. I need not point out the trifling differences between the two areas, 

 and have only referred to both, that it may be seen, it is a well denned Zoo- 

 logical region, and that any argument based upon its Fauna is a fair one. 



From Dr. Staudinger' s catalogue, and the lists of British species, I have 

 prepared the following table, which I think will be easily understood. — 





Palaearctic 



British 









Species. 



Species. 



Proportion. 



Butterflies 



... 456 ... 



64 ... 



about 1 in 7 



Burnets 



... 75 ... 



9 ... 



>> 



1 in 8 



Hawks 



... 110 ... 



..,.^.33 ... 



a 



1 in 34 



Bombyces 



... 369 ... , 



... 105 ... 



}) 



1 in 3£ 



Noctuas 



... 1040 ... 



... 321 ... 



}} 



1 in 3i 



Geometers . . . 



... 799 ... . 



... 282 ... 



)> 



1 in 2| 





2393 



750 





1 in 3i 



Taking the above table as a whole it is clear that in proportion to the 

 other groups ( except the Burnets), either singly or together, we have less 

 than half the number of butterflies that we ought to have. That while of 

 the larger Heterocera, 1 species is found in Britain for every 3| found over 

 the whole of this extensive district, we have only 1 butterfly for every 7 

 found over the same territory. The calculation may be made another way. 

 The number of butterflies and moths occurring in this region is 2849, of 

 which 456 are butterflies, being about One-Sixth of the whole. In Britain 

 the total number found is 814, of which the 64 butterflies are but One- 

 thirteenth of the whole. Whichever way, therefore, we compare the 

 numbers, the result shows that less than half of the proportionate number 

 of butterflies occur here. 



