Ux 



and of some works on European Coleoptera, has furnished me 

 with the following list of genera which are wholly apterous, and 

 which ahound in South Europe and North Africa. 



Carahus, possesses ahout 80 species in these regions; hut is 

 wholly ahsent from Madeira. 



Thorictus,has 10 South European species, and one representa- 

 tive in Madeira, which is an ants'-nest species. 



Ehizotrogus (Melolonthidfe), 27 species in Sicily and Algeria, the 

 very countries to which the Madeiran fauna is traced, yet it is 

 wholly absent. 



Lampyris, Drilus and Troglops (Malacoderms), of which the 

 females are apterous, possess 27 South European and North 

 African species ; none in Madeira. 



OtiorJiynchus, Brachycerus, and twenty other genera of Cur- 

 culionidae, comprising more than 300 South European and North 

 African species, are absent from Madeira, with two exceptions. 

 One is the Trachyjjhloeus scaher, a widely-spread European insect 

 often found in ants' nests ; and this, with the case of the Thorictus, 

 renders it probable that ants'-nest species have some unusual 

 means of distribution, which are by no means difficult to conceive. 

 The other exception is that of the genus Acalles, which has a 

 number of Madeiran species, all peculiar, and is very abundant 

 in all the Atlantic islands. Now we have first to remark that 

 Acalles is an isolated form, but is allied to Cryptorhynchus, which 

 is often amply winged ; so that we may easily suppose that its 

 introduction to Madeira took place before it became completely 

 apterous in Europe. In the second place we have the fact, that 

 many of the species are confined to peculiar herbaceous and 

 shrubby plants, in the stems of which they undergo their trans- 

 formations, and which habit would afford facilities for their 

 occasional transmission in the egg or pupa state across a con- 

 siderable width of ocean, while a fragment of dry stem containing 

 egg or larva might possibl}^ be carried some hundred miles or 

 more by a hurricane. Such suppositions would not be admissible 

 to account for numerous cases of transmission, but, as will be 

 seen, this is almost the only example of a genus of large-sized 

 apterous European beetles occurring in Madeira. 



Pimelia, Tentyria, Blaps, and eighteen other genera of 

 Heteromera, comprising about 550 species of South Europe and 

 North Africa, are totally absent from Madeira, with the following 



