THE YOUNG NATURALIST. 



6; o 



is there any evidence in support of the opinion that our existing butterflies 

 are fewer in number than they once were? I think there is such evidence. 



In the first place the earlier writers on Entomology mention a considerable 

 number of species as natives of Britain, that are not now to be found. This 

 has been explained away by supposing some of the records to be mistakes, 

 and others to be captures of accidental visitors. But there seems no more 

 reason for doubting the authenticity of some of them, than of disputing the 

 actual occurrence of the Large Copper five and twenty years ago. Many of 

 them were species that ought to have been found here, the British isles 

 being fairly within their range. 



Secondly, I do not find that anything like the same proportion of species 

 in other groups are becoming rare or extinct. A few species may have 

 done so, but none that were even generally abundant, and in every group 

 the new additions to our fauna has far exceeded those that have disappeared 

 or become rare. It is true that our desire to increase our collections, to 

 add more species to those existing, had led to the inclusion in our lists 

 of species of which but a chance specimen had been taken, and whose 

 native haunts were far from our shores. Thus, S. Phcegea and N. Ancilla 

 are found in our exchange lists, to the bewilderment of beginners, and the 

 advantage of no one but the dealers who supply Foreign types. Species 

 included in this way are soon dropped out again, but what I say above 

 is not intended to apply to these chance visitors at all. 



I tried to find some country resembling Britain in natural conditions and ex- 

 tent that I might in the third place compare the butterflies found there with 

 those that are natives here. This 1 failed to do, and had there been such a place 

 it is a chance if I could have obtained the requisite data for instituting a com- 

 parison. I have therefore taken for this purpose the Lepidopterous Fauna 

 of the whole of the Palsearctie Eegion, which is defined by Wallace as fol- 

 lows : " This very extensive region comprises all Temperate Europe and 

 Asia, from Iceland to Behring Straits, and from the Azores to Japan. The 

 Southern boundary is somewhat indefinite, but it seems advisable to comprise 

 in it all the extra-tropical part of the Sahara and Arabia, and all Persia, 

 Cabul, and Beloochistan to the Indus. It comes down to a little below the 

 limits of forests in the Himalayas, and includes the Northern half of China, 

 not quite so far down the coast as Amcy." Professor Wallace has arrived at 

 his conclusions in defining the various region from an examination of the 

 Yertebrata inhabiting them. " The Paleearctic region/' he says, " is well 

 characterized by possessing 3 families of vertebrates peculiar to it, as well as 

 35 peculiar genera of mammalia, and 57 of birds, constituting about one- 

 third of the total number it possesses. These are amply sufficient to char- 



