THE CHIEF COLEOPTEROUS FAUNAE. 



63 



draw useful reflections from it, both general and particular. An 

 important general reflection is that, whenever we see a homoge- 

 neous fauna (I am speaking of faunas, but the observation ap- 

 plies equally, or nearly so, to floras), we may rest assured that 

 that is the first fauna which established itself after the land 

 emerged from the sea and became capable of sustaining animal 

 life, and that we must look upon all patches, encroachments, or 

 overlayings of a different character, as attempts of some subse- 

 quent intruders to establish themselves among the older inhabit- 

 ants. We see, too, how there is no inconsistency in a colony 

 marching rapidly across a raised sea-bottom, while it is arrested 

 the moment it reaches the other side. Coming to particulars, 

 this may prove useful in sometimes helping us to a date. Thus 

 we may argue from the faunas of India and Africa that these 

 countries were once continuous and united, and that they were 

 disjoined before the Cape received its contribution from Australia ; 

 for there are types common to Africa and Australia which do not 

 occur in India. 



The relation between the Coleoptera of Brazil and West 

 Africa furnishes so very apt an illustration of the value of such 

 indications, and the use that may be made of them in tracing the 

 past history of geographical changes, that I may be excused anti- 

 cipating a little what I have to say on the subject of these faunas. 



A few years ago I read a paper to this Society, in which I 

 pointed out the existence of the Brazilian element in Old Ca- 

 labar. I believe that paper was closely scrutinized at the time 

 (in fact, I know it was) by some of our best entomologists, who 

 looked askance at it at first, but ended by admitting that I was 

 right. Since then I have gone on, from time to time, describing 

 the new species from Old Calabar in the 'Annals of Natural 

 History ; ' and I do not believe there has been one of my papers in 

 which I have not had to record the Brazilian element as again 

 and again appearing. The same thing is observed at Senegal 

 and Guinea, and Gaboon - ; and it has also now been recognized in 

 the Lepidoptera also. 



The evidence thus given of the presence of an important infu- 

 sion of Brazilian type in the West-African fauna seemed to me 

 sufficient to place the fact beyond dispute ; and I would not now 

 have troubled the reader with any further proof of it, had it not 

 been for an expression of opinion which has fallen from our much- 

 respected President between the reading of this paper and the 



