VERTICAL DISTRIBUTION OF THE LEPIDOPTERA. 345 



siderable distances, in search of food. Now, if these insects 

 have no sense of direction whatever, how can they find their 

 way back as accurately as they do ? " They find their way by 

 the use of landmarks ! Disturb a bee, and it will circle round 

 and round like a carrier-pigeon. Here is a hive only a few 

 hundred yards from the sea. Twenty bees are liberated on the 

 shore, and not one of them returns ! Another lot set free on a 

 lawn two hundred yards away — another unaccustomed place — 

 are equally unable to find the hive ! Forty ants feeding on 

 some honey placed on a square of glass close to their nest are 

 removed fifty yards off. They all lose themselves ! Now, I 

 pause to consider what would be the result were this a lay 

 instead of a scientific explanation. One of my critics, I fear, 

 would betake himself to the seat of the scornful ; another to 

 bone-picking — rest and refreshment ? But the explanation is 

 that of Sir John Lubbock, of Mr. Eomanes, of Mons. Fabre. 

 The experiments I very briefly quote will be found described at 

 length, with others, in 'The Senses of Animals' (Sir J. Lubbock), 

 chapter xiii. 



Chester, November 2ncl, 1896. 



ON THE PREPONDERATING INFLUENCE OF THE OR- 

 GANIC OVER THE PHYSICAL ENVIRONMENT IN 

 DETERMINING THE VERTICAL DISTRIBUTION OF 

 THE LEPIDOPTERA. 



By W. Harcourt-Bath. « 



In endeavouring to elucidate the various problems connected 

 with the vertical distribution of the Lepidoptera in the different 

 and diverse mountain systems in Europe, a great many factors 

 have to be taken by the student into consideration. 



The hypothesis of the glacial epoch and the subsequent 

 amelioration of the climate supply us with the means of gauging 

 the indirect action of the physical conditions which have oper- 

 ated to produce the present result. But a little further insight 

 into the subject at the same time will enable us also to estimate 

 and appreciate the preponderating influence exerted by the 

 organic over the physical environment. 



Although many hold that the mere effect of the climatal 

 conditions (especially the temperature and precipitation) are by 

 themselves the principal factors in deciding the vertical distri- 

 bution of the great majority of species, I am perfectly convinced 

 personally that such is not the case, but that they do in point of 

 fact play quite a subordinate part in the determination, although 

 they may be in a good many instances the indirect cause thereof. 



