170 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



from a very brief study of the physiological characteristics 

 of the Coleoptera, as of any other order of insects, that the 

 species themselves clearly fall into two groups, which we 

 may call the adaptables and the non-adaptables, or, if we 

 like, the progressives and the conservatives — that is, 

 species which are common everywhere, and species which 

 are either generally rare or common only locally ; in other 

 words, there are a certain number of forms which have 

 successfully solved the problem of the continual adjust- 

 ment of themselves to an ever-changing environment, and 

 those who, failing to do so, perish when their own par- 

 ticular environment ceases to be. These latter certainly 

 form the bulk of the species. There are Beetles attached 

 to the sandy wastes of the shore, to marshes, forests, 

 heaths, mosses ; and when you turn your sandhills into 

 docks and golf links, drain your mosses and bogs, cut 

 down your woodlands and cultivate your desert wilder- 

 nesses, then the non-adaptable, the conservatives of the 

 feral population of such places, pass to return no more ; 

 they are incapable of the necessary new adaptations. 

 Hence it is that inasmuch as the physical characteristics 

 of this country are continually changing, and that at an 

 increasing ratio, the extinction of most of our conservative 

 species of animals is merely a matter of time. This pro- 

 cess has almost completed itself among the mammals, is 

 in full swing among the birds, and is quite noticeable 

 among such an insect group as the Diurnal Lepidoptera. 

 It must, however, be admitted that there is no evidence of 

 any extinction of specific forms among the Coleoptera as 

 yet, and I have, perhaps, rather exceeded the strict lines of 

 my subject on this point, because I want to impress the 

 distinction between such species, which are the only ones 

 that are of any service to us, in our endeavour to discover 

 the derivation of any of them — between these and those 



