260 STUDIES, SCIENTIFIC AND SOCIAL chap. 



hardly impute such a constant and overwhelming pre- 

 ponderance 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 suffi- 

 ciently 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 ar- 

 gument, although a valid explanation of some portion of 

 the facts, if we admit that many of the latter have been 

 recently introduced hy oiatural causes, cannot be used by 

 those who maintain a former land-connection as the sole 

 origin of the fauna ; for on that theory all the species now 

 inhabiting the island (and not introduced by man) must 

 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 i3robable 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 obscuroguttatus, 

 Calathus fuscus and Bradycellus f%dvus. 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 there- 

 fore 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 we have those genera which, though apterous in 

 Madeira, are wholly or partially winged elsewhere. These 

 comprise a large number of species, and are twenty-two 



