Ivi 



Madeira would be without a single native rodent, or even a frog, 

 if tliey owed their rich coleopterous and molluscous faunas to 

 land-connection with Europe ? 



The exhaustive researches of Mr. WoUaston in these islands 

 will, I believe, furnish, in the single order of Coleoptera, ample 

 materials for the elucidation of this very interesting question. 

 Although the 'Insecta Maderensia' has now been published more 

 than sixteen years, the vast store of facts which it contains 

 bearing on the question of geographical distribution, and espe- 

 cially on that of insular faunas, has never been fully appreciated ; 

 and as Mr. Murray has by no means grappled with these facts as 

 a whole, or attempted to show how they are compatible with his 

 theory, I think I cannot better occupy your time than in giving 

 a somewhat detailed analysis of them, and pointing out what 

 I conceive to be their true bearing on the problem of the mode 

 of distribution of beetles, and the origin of insular faunas. My 

 interpretation of the evidence may be erroneous, but the facts 

 themselves must be of value. 



I propose to confine myself mainly to evidence furnished by 

 the Coleoptera of the Madeiran group, because, being separated 

 from the mainland by a much wider extent of ocean than either 

 the Canaries or Cape de Verdes, it offers a much more satis- 

 factory test of the opposing theories. It is an advantage also 

 that the materials are, in its case, by far the most complete ; and 

 in the ' Insecta Maderensia ' Mr. Wollaston has given some 

 details of importance which are wanting in the ' Coleoptera 

 Atlantidum' and in the 'Coleoptera Hesperidum,' The most 

 novel and striking facts brought out by Mr. Wollaston's re- 

 searches in Madeira are, as is well known, — 1st. The affinity 

 with the Mediterranean fauna ; — 2nd. The total absence of certain 

 large divisions of Coleoptera abundant in that fauna;— 3rd. The 

 number of new and peculiar species and of new and anomalous 

 genera; — and 4th. The unexampled preponderance of apterous 

 species. Now accepting, as Mr. Murray does, the theory of slow 

 change of forms by natural causes, we may take the first and 

 third of these facts as proving that the origin of the Madeiran 

 fauna is of a very ancient date. Let us see therefore how the 

 second and the fourth set of facts bear upon the mode of its 

 origin, whether by a land-connection with Europe or by trans- 

 mission across the sea. It will be convenient to take first the 



