THE FORMATION, ETC., OF A COLLECTION OF INSECTS. 295 



the collection made with reference to the two at the same time. 

 In order to provide a proper and uniform basis to work upon, I 

 have prepared a series of maps, tables, rules, and formulae for 

 my guidance. 



The maps consist of two series. In the first, which illus- 

 trates the zoo-geographical regions, the world is divided into six 

 regions and twenty-four subregions, after A. E. Wallace. Each 

 of these subregions I propose to study, and deal with in detail 

 one by one. At present I am confining my attention to the two 

 subregions in which the Continent of Europe is included. My 

 idea is to work out the geographical distribution of each species 

 of Khopalocera in the area indicated. With this object in view 

 I have prepared another map illustrating the provinces and sub- 

 provinces, founded upon the principal river basins and other 

 important physical considerations. A third map in this set 

 serves in a similar way to illustrate the subprovinces in the 

 British Isles. All these geographical divisions and subdivisions 

 are differently coloured, and it is proposed Liter on to have the 

 data labels similarly coloured in order to correspond with them ; 

 but of these more anon. 



A second series of maps, consisting of three likewise, serves to 

 illustrate the annual isotherms throughout the globe, in Europe 

 and the British Isles, in addition to the zones of vegetation 

 encountered between the equator and the poles. These are 

 supplemented by tables giving the altitudes of the corresponding 

 vertical zones of vegetation upon all the principal mountain 

 ranges in Europe. 



My aim is to obtain a series of every species possible from 

 all these numerous geographical and climatalogical (= vertical) 

 subdivisions, or as many of them as I am able. The principal 

 points which I bear in mind are, firstly, to obtain as typical a 

 collection of the Khopalocera Fauna of each subdivision as 

 possible ; and secondly, to procure specimens illustrating the 

 limits of variation of each species in them, special attention 

 being directed to seasonal dimorphism. 



This system has several drawbacks, the principal of which 

 is the immense amount of room which each species occupies, 

 especially in the case of those which possess a wide distribution, 

 vary considerably in different parts of their range, and have 

 several broods in the year. But the scientific advantages far 

 outweigh any inconvenience occasioned by the vast amount of 

 space required to carry it out. All the data labels which I 

 employ correspond with the maps and tables above described, 

 figures and letters being given instead of long particulars, the 

 key to which is very simple. Every specimen is in addition 

 labelled individually with a consecutive number which corre- 

 sponds with a catalogue, wherein are entered full particulars of 

 date, locality of capture, &c. The data labels illustrate the 



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