Ix 



interesting exceptions: — two common species oi Blaps, which are 

 admitted to have been introduced by human agency, and three 

 species of Meloe, two of which are European and one peculiar. 

 The means by which the apterous, shiggish and bulky Meloes 

 were introduced is sufficiently clear, when we remember that the 

 minute active larvae attach themselves to bees, insects of 

 exceedingly powerful flight, and more likely than perhaps any 

 others to pass safely across 300 miles of ocean. That the solitary 

 exception to the absence of wholly apterous genera of European 

 Heteromera from Madeira should be the genus Meloe, is, therefore, 

 one of those critical facts which almost demonstrate that it is not 

 to land-continuity with the continent that the island owes its 

 insect fauna. 



Timarcha. This, the only important apterous genus of Chryso- 

 melidffi, is especially abundant in Spain and Algeria, and possesses 

 forty-four South European and North African species ; yet it is 

 unknown in Madeira. 



The occurrence of two isolated European species of characteristic 

 Atlantic apterous genera — Tari:)hius and Hegeter — may seem to 

 favour the opposite theory. The Tarphius gibhulus occurs in 

 Sicily, and is the only European species of the genus, of which 

 about forty inhabit the Atlantic islands. It is most nearly allied 

 to the smallest of the Madeiran species, T. Loivei, which is 

 abundant among lichen on weather-beaten rocks and even ascends 

 in the forest regions to the highest branches of the trees. These 

 habits, with its minute size, are all in favour of this species, or 

 some ancestral allied form, having been carried across b}'^ the v/inds 

 or waves, thus transferring, to Europe one of the peculiar types 

 elaborated in the Atlantic isles. The Hegeter tristis is an analogous 

 case, this species of an otherwise exclusively Atlantic genus having 

 occurred on the opposite coast of Africa. These instances will 

 furnish a reply to one of Mr. Murray's difficulties, — that all the 

 migration has been in one direction, from Europe to Madeira, never 

 from Madeira to the continent, — a difficulty, it may be remarked, 

 which is wholly founded on an unproved and unprovable assump- 

 tion ; for how can it be determined that, in the case of Acalles for 

 example, the genus had not been first developed in the Atlantic 

 islands and then transferred to Europe, instead of the reverse ? 

 It is always assumed to have been the other way, but I am not 

 aware that any proof can be obtained that it was so, and it is 



