SCIENCE-GOSSIP 



37 



though often quite close to the railway side. Last 

 September I observed on some muddy banks of the 

 river between Queenstown and Cork, within ten 

 yards to a hundred yards from the train, flocks of 

 gulls, herons, waders of several species, and other 

 birds feeding as the tide was receding. As the train 

 passed a few took the trouble to lazily fly, the 

 majority remaining undisturbed within fifty paces 

 of the engine as it swept past. This was the more 

 notable to me as I had just previously gone through 



of us, shown a tendency to become dark in colour 

 in parts of Lancashire, Cheshire, and Yorkshire 

 ( )f these may be instanced two common species 

 which are here figured, viz , Amphtdasys betularia 

 and Tfphrosiabiundularia. Within my own memory 

 the dark forms of both these species were so rare 

 as to command high prices among collectors, 

 whilst now they are more common than the types 

 in some parts of those counties, and appear to be 

 spreading. Melanism does not account wholly for 

 these changes from light forms to dark. It is 

 more probably caused by the darker forms finding 

 their colour more protective while resting on the 

 smoke-blackened trunks of trees, and thus surviving 

 to perpetuate their variation. It should be 

 remembered that only within this century has coal 

 been used to any large extent. It is curious to note, 

 and I think I am correct in so saying, that it is those 

 moths which show a tendency to darkening colour 

 in the manufacturing districts which chiefly rest 

 during daytime on trunks of trees. To those 

 named may be added Aplecta nebulosa, and quite 

 recently there has appeared an almost black race of 

 Phigalia pedaria (pilosaria) which has established 

 itself under, I am told, like circumstances. 



Another department is the migration of plants 

 and animals, which invariably appear to follow 

 man as he colonizes and civilizes new countries. 



Amphidasys BF.TL'I.ARIA. 

 Type and dark form. 



the great Canadian forest at the head of Lakes 

 Huron and Superior. Neither going out nor re- 

 turning over that long forest ride of nearly a 

 thousand miles each way did I see any number of 

 birds near the line. The Canadian Pacific Railway 

 has been opened less than ten years, so the animals 

 have not yet become hereditarily familiar with 

 snorting engines and attendant trains. Conse- 

 quently one is impressed with the apparent total 

 absence of visible life among the higher orders. 



The joke told against our fellow-countrymen of 

 North Britain, that there " the crows know when 

 it is the Sabbath Day," is possibly founded on a 

 stratum of truth ; for birds appear to quickly learn 

 when safe from their natural enemies. 



Another important influence on the fauna of a 

 country highly civilized is the effect of drainage 

 and cultivation of the land. Some animals and 

 plants disappear, whilst others become established. 

 For instance, take the corn-plants found where 

 much grain is grown, which are hardly known in 

 wilder districts. 



The effect of smoke in blackening the surround- 

 ing landscape in manufacturing districts appears 

 to be making itself felt in a remarkable manner on 

 the lepidopterous fauna living there. Several 

 species of moths have, within the lifetime of many 



Tephrosia BIUNDULARIA. 

 Type and dark form. 



This, however, is too large a matter to now enter 

 upon . 



In an article such as this when space is limited, 

 it is impossible to deal fully with such a wide 

 and interesting subject ; but we trust it may 

 induce collectors and students to record their 

 experiences. These pages are open for such 

 welcome material towards obtaining a better 

 knowledge of the cause of this local change in 

 colour of some species, and the establishment or 

 disappearance of other species, through man's 

 influence. 



