Ixii 



apterous to only 110 winged ! We can hardly impute sucli a 

 constant and overwhelming preponderance to the fact that 

 apterous insects have less facilities for extending their range, 

 when we know that nearly every apterous genus possesses species 

 of almost universal European distribution. I may here recall the 

 fact, that of the above-mentioned 14 apterous species which range 

 out of Madeira, two are Meloes and two ants'-nest beetles, whose 

 presence we have already suQjcientl}'^ accounted for. It may no 

 doubt be said that much of the difference here shown is due to 

 the fact that the peculiar Madeiran species have had time to 

 become apterous, while the species common to other countries 

 have not yet had time to lose their wings ; but this argument, 

 although a valid explanation of some portion of the facts, if we 

 admit that many of the latter have been recently introduced by 

 natural causes, cannot be used by those who maintain a former 

 land-connection as tbe sole origin of the fauna ; for on that theory 

 all the species now inhabiting the island (and not introduced by 

 man) mu^t date back to the same remote period, and have had 

 equal time in which to be modified. 



Let us now consider what are the special relations of the 

 apterous Madeiran species as throwing light upon their possible 

 or probable mode of introduction. 



We have three species which Mr. Wollaston himself states to 

 be usually winged elsewhere, but which are apterous in Madeira. 

 These are Metahletus ohscuroguttatus, Calathus fuscus and Brady- 

 cellus fidvus. I am inclined to believe that there are a few others 

 which will come under this category'-, but it is very difficult to get 

 information as to the winged or apterous character of particular 

 species. These insects, however, have evidently become apterous 

 since their introduction into Madeira. We have therefore no 

 difficulty in accounting for their introduction, and, as no other 

 change in their external characters has been effected, we may 

 suppose it to have been comparatively recent. 



Next vve have those genera which, though apterous in Madeira, 

 are wholly or partiall}'' winged elsewhere. These comprise a large 

 number of species, and are twenty-two in number, as follows : — 

 Carabidse : Cymindis, Dromius, Metahletus, Scarites, Apotomus, 

 Loricera, Leistus, Calathus, OUstho]jus, Argutor, Cratognathus, 

 Bradycellus, Trechus. Philhydrida : Hydrohius. Byrrhidae : 

 Syncalypta. Curculionidi© : Phloeophagiis, Tychius, Smic7'onyx. 



