62 THE entomologist's keoobo. 



one has in one's cabinet a certain number of species, or some rare sorts 

 which nobody else possesses, is surely an ambition quite unworthy of a 

 true entomologist." 



Although collecting, then, must always be considered as a legitimate 

 part of an entomologist's work (nay, up to a certain point, as a neces- 

 sary and important part), yet if a person's pursuit of entomology stops 

 short at collecting, he is about as much a scientific entomologist as a 

 butcher is a comparative anatomist or a physiologist. In the pursuit 

 of his study the entomologist will find a great part of his material in 

 the living insects which are the objects of his tender care and solicitude. 

 The habits of species may be well known, but what relationship do 

 these habits bear to the environment of the species ? The colours of 

 larvae may have been well-described, but what is the meaning of a 

 particular mark or a particular spot ? The differences between two 

 closely allied butterflies may have been very carefully worked out, but 

 what has brought about these differences ? Two different forms of the 

 same insect may be known, but what is the cause of the difference ? 

 The polymorphism of a moth is exceedingly interesting, but what 

 inherent factor has produced the polymorphism ? And here even the 

 best stop at present. What are the inherent factors that produce, 

 determine and guide the forces which result in variation ? We theorise ; 

 we think that we have solved a jDuzzle, only to find that some one 

 detects an error in our data, a defect in the foundation of our theory, 

 and down comes the super-structure to the ground. But destructive 

 criticism is much easier than the formulation of a new theory to put in 

 the place of what we destroy. Nevertheless, we find, in spite of the 

 searching criticism to which every new theory is subjected, that a great 

 deal of solid headway has been made. When a man observes a 

 phenomenon, his first question should be — What is the cause of it? 

 When he attempts to answer the question and starts his theory he must 

 ask himself — Can I knock a hole in the bottom of it ? If he cannot, and 

 if other scientific students cannot, then the theory must stand as an 

 explanation of the fact until something better can be put in its place. 

 This, in truth, is the basis of all scientific study, which makes men, if 

 they will, find — 



" Books in the running brooks, 

 Sermons in stones, and good in everything." 



The excellence of British collections of Lepidoptera has always been 

 conceded, and the extent of the insect fauna of the British Islands, in 

 comparison with that of other countries of equal or greater area, is very 

 noticeable. The known Tortriges of the Palasarctic area, total up to 

 about 650 ; of these, above 350 are British. Almost 50 per cent, of 

 the known Pala^arctic Tineina (taking this group in its old and widest 

 sense) are to be found, and so on. We have in Britain two-thirds of 

 the number of insects to be found in the whole of Grermany and 

 Switzerland combined. It is not at all difiicult to understand 

 whv this is so. No country in the world of equal area presents the 

 same diversities in its geological characters as do the British Islands, 

 and I need not point out how intimate is the connection between the 

 geology of a country and its flora, and between the flora and the insect 

 fauna. The varying geological conditions give us a flora, large both 

 in the number of genera and relatively in the number of species, and 

 this is sulhcient to account for the fact that we have so large a percent- 



