126 [November, 



NOTES ON THE LEPIDOPTERA OF THE BIEMINGHAM DISTEICT : 



A RETEOSPECT. 



BY W. HAECOURT BATH. 



The ordiuary observer could not have failed to Botice the changes 

 which have taken place in the Fauna and Flora of the Birmingham 

 District within the last fifty years. 



The Fauna and Flora of any country or district are not absolutely 

 identical for any two successive periods, however brief. Some species 

 are gaining ground, others losing it, while yet others remain practically 

 stationary amidst their many fluctuations. These changes are per- 

 petually going on, but very few of them are placed on record. 



In the course of a few years, the general changes may be 

 inappreciable to the ordinary observer, but, locally, there are often 

 considerable changes which cannot fail to be detected by close scrutiny. 

 These changes are links in the great chain of changes whereby the 

 Fauna and Flora of one geological period are considerably modified 

 and gradually converted into the Fauna and Flora of the succeeding 

 period. But, in the different groups of animals and plants, these 

 changes progress at markedly different rates. Some will change 

 rapidly, while others will hardly change at all. 



As a general rule, the change seems to be slowest among the least 

 specialized forms and among those which have been established the 

 longest — the most speedy among the most specialized forms and such 

 as have only lately been introduced. 



The Lepidoptera in particular have undergone many great and 

 important changes— even during the last few years. The lists of 

 fifty years ago are no longer trustworthy guides. 



We have records of many species occurring in the district which 

 are now extinct. Others, which were very plentiful, are now only 

 occasionally seen. Others, again, which were widely distributed 

 throughout the area of theTameV alley, have become restricted, perhaps, 

 to one or two localities, and so reduced in numbers that we may safely 

 venture to predict that within a few years hence they will be entirely 

 extirpated. On the other hand, there are very few species multiplying 

 their numbers or widening their area of distribution to compensate us 

 for such losses. 



I will now proceed to give a few examples to illustrate my 

 argument : — 



Not many years ago, probably even within the last fifty or sixty years, the 

 gorgeous swallow-tail (Papilio MachaonJ used to roam tliroughout the Midlands. 



