INTROBTJCTORY REAIARKS. XI 



were chance introductions (such as have occurred, to my own certain 

 knowledge, in trading-vessels) from the opposite coast of Morocco. 



Although many widely spread genera (such as Carahus, SUpha, 

 Tentyria, and Pimelia) are represented at the Canaries which are 

 absent from the Madeiras, nevertheless, on the whole, I think that 

 the latter Group is, in proj)ortion to the aggregate superficies of its 

 separate parts, the more productive of the two. Probably, however, 

 this is merely owing to the greater depauperation of the former 

 through the destruction of the timber, and (as a necessary conse- 

 quence) the gradual drying up of the pools and streams — which 

 there is abundant evidence to show were once numerous. But, be 

 this as it may, the fact itself seems plainly indicated by the relative 

 extent of their Coleopterous faunas — that of the Madeiran archi- 

 pelago numbering, up to the present date, 660 species, whilst that of 

 the Canarian one (the product of seven large islands) includes hitherto 

 but 930. We must undoubtedly bear in mind that the Madeiras 

 have been more thoroughly examined than the Canaries ; yet, even 

 whilst making a liberal allowance for this consideration, I do not 

 believe that the Canarian Coleoptera will ever prove to be so nume- 

 rous in species, in proportion to the area ranged over, as the Madeiran. 

 Nor have the two faunas quite so decided a resemblance as I should 

 have a priori anticipated, seeing that 224 species is all that they 

 have yet been demonstrated to possess in common. There are, how- 

 ever, a certain number of ordinary (perhaps naturalized) forms, in 

 both cases, which we may feel quite sure will be shown, sooner or 

 later, to be mutual ; therefore we may safely imagine the above 

 number as raised, at all events, to 250. Yet even that proportion is 

 but a small one, in islands so manifestly belonging to the same geo- 

 graphical system, and with their many physical peculiarities nearly 

 similar. 



Adverting to the general statistics, it is interesting to observe 

 that the great Sections (whatever their relative positions may be, in 

 a system of classification) into which the Coleoptera are usually 

 supposed, either by acknowledgment or tacit assumption, to be sub- 

 divided bear pretty nearly the same numerical proportions amongst 

 themselves in the two Groups. Thus, in both instances, the Bhyncho- 

 phora exceeds every other department in the nimiber of its representa- 

 tives ; whilst the next in order is the Bracheh/tra : and the Eucerata 

 and Hydradephaga occupy, either actually or almost, the lowest posi- 

 tions. The Heteromera at the Canaries follows third in numerical 

 succession, and is more pronounced than at Madeira ; whilst the 



