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Australia, perhaps West Indies, and so forth, being considered 

 sufficient. This brings out the leading facts of distribution very 

 well, such as the restriction of many genera and groups of genera to 

 each of the great divisions, and the distinctive facies which all the 

 products from one region possess ; but we seldom see it carried 

 further, and it remains a pretty association of Geography with 

 Natural History, and no more. Eesults infinitely more suggestive 

 are brought about if the student labels each specimen with its 

 locality, instead of recording it on the ticket which bears the 

 specific name placed below all the specimens, and if he is fortunate 

 enough to be able to amass a large suite of specimens, accurately so 

 ticketed, of genera abounding in local varieties and closel^^-allied 

 species. Indications of the conditions under Avhich varieties, local 

 races, and x^erhaps species, are formed in Nature, are revealed by 

 this method, and a field of investigation is opened which connects 

 the study of a few insect species with some of the most difiicult 

 problems that are now engaging the attention of philosophers. The 

 most common event that happens, when a student works at a series 

 of species in this way, is the discovery that even the most constant 

 species vary in some parts of their area of distribution ; the next, 

 that a small well-marked difference in a species is generally a local 

 difl:erence, and embraces all the individuals of the district in which 

 it occurs. As the collection increases, further curious facts come 

 out. It is found, for instance, that some highly -variable species 

 give rise to one set of varieties in one area, another distinctly 

 different set in another area, and so on ; and further, that in some 

 areas one, or perhaps more, of these variations will be better marked 

 than, and preponderate in number over, the other varieties of the 

 same species. Still further, it is found that in some districts one 

 such variety alone occurs, having apparently prevailed over all the 

 others. To be properly impressed, however, with the great truth 

 and reality of these facts, the student should himself have travelled 

 as an Entomological collector over an extent of country embraced 

 by many local varieties of variable species ; otherwise his attention 

 will not be suiSciently excited to the curious facts Nature presents 

 to him, and he will not take the trouble to amass and obtain the- 

 exact localities of numerous specimens of common variable species. 

 Perhaps the most important result of this attention to distribution 

 of varieties is that a fine gradation of forms or degrees of variation 

 will be found, from the "sport" or variety, such as is liable to be 



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