NOTES ON THE DISTRIBUTION OF THE BRITISH COLEOPTERA. 147 



that the $ there hiys her eggs. Thus he accounts for the fact that, 

 in spite of the hxrge numbers that fly off, the whole district through 

 which the flight passes is kept populated, although one is inclined to 

 dissent from an exphmation of a phenomenon, that leaves the greater 

 part of the district whence the flight originates to be populated by the 

 remainintj remnant of nature's failures. 



Notes on the distribution of tlie British Coieoptera. 



By W. E. SHARP, F.E.S. 



" If we take the organic productions of a small island, or of any 

 very limited tract of country, such as a moderate sized country parish, 

 we have in their relations and affinities — in the fact that they are 

 there and others are not there — a problem which involves all the 

 migrations of these species and their ancestral forms, all the vicissi- 

 tudes of climate and all the changes of sea and land, which have 

 affected those migrations, the whole series of actions and reactions 

 which have determined the preservation of some forms and the 

 extinction of others, in fact, the whole history of the earth, inorganic 

 and organic throughout a large portion of geological time." 



In these words does so eminent an authority as Dr. Wallace in a 

 recent work, define the problem of the present distribution of the flora 

 and fauna of the earth, and show how, among the many questions 

 submitted to the biologist, few in interest and in complexity exceed it. 

 In fact, faunistic distribution is a department by itself in biology, 

 volumes may be written and the research of a life-time devoted to its 

 elucidation, and yet students who have considered the subject most 

 deeply, are most aware how dimly and partially can its phenomena be 

 understood, and how tentatively and provisionally can any theories be 

 formed on the subject. So vast a problem, however, admits of attack 

 in detail, and I propose in these papers briefly to consider what 

 material a study of the present distribution of one order of insects in 

 Britain can afford, towards some comprehension of their derivation 

 and the order of their arrival here. Insects from their antiquity, 

 their specific and individual abundance and omnipresence, offer, 

 perhaps, better and more cogent evidence, in an enquiry of this kind, 

 than does any other part of our terrestrial fauna ; their antiquity as a 

 distinct class is indeed immeasurably great ; as far back at least as the 

 carljoniferous series, forms referable to existing orders appear, while 

 fossil coieoptera generically allied to existing species, have been found 

 in English oolitic and cretaceous deposits. Indeed, it appears a safe 

 conjecture that in tertiary times — when the mammalian fauna must 

 have been very unlike what it is to-day — the phylogenetic development 

 of the Insecta had arrived at a stage from Avhich but little deviation 

 has been made since. But in any consideration of the distribution of 

 our British insects we need not follow the stream of evolution to such 

 remote springs as these. Our entire insect fauna is, with a few 

 doubtful exceptions, merely an extension of that of north-western 

 Europe, and the geologically recent severance of the connection 

 between these islands and the continent, prevents it having acquired 

 any very distinct insular characteristics. 



The order we propose especially to consider in these notes, is that 

 of the coieoptera, which, from its universal distribution and specific 



