"290 Proceedings of the Royal Irish Academy. 



•same time, it may also be interesting to quote his opinion on the fauna of 

 the Atlantic Islands. "How the European character," he says, "of this 

 general fauna is to be accounted for, except on the supposition of a 

 former connection of them all with Europe, and how the presence of 

 these special forms of the same sub-fauna in all tlie islands and 

 nowhere else, is to be accounted for except on the supposition that, after 

 ihey were disunited from Europe, they were still united among them- 

 Belves, it is for those who advocate the theory of dispersal by chance 

 introductions to say" (A, p. 14), 



Having made a careful study of the Coeloptera of the Atlantic 

 Islands, "Wollaston states that his own views are more in accordance 

 with those propounded by Murray than with the theory of exceptional 

 atmospheric dissemination so ably advocated by Dr. Wallace (A, p. 209). 

 He aptly remarks (A, p. 210) that storms and hurricanes, so much 

 relied upon by the latter for the aerial transmissal of European species 

 to the Atlantic Islands, are not only rare in these latitudes, but blow 

 almost invariably from the south ; and that the apterous, rather unwieldy 

 forms, so largely represented on those islands, are the least suitable for 

 atmospheric propulsion. 



In their European and North African character, the Neuroptera of 

 the Atlantic Islands agree perfectly with the above-mentioned orders 

 of insects. M'Lachlan says of the Madeiran species : ' ' That some of the 

 purely terrestrial forms may have been introduced from Europe is 

 very possible ; on the other hand, I see no reason to doubt that some 

 of tlie European forms mentioned may be considered true natives of 

 the islands also. It is worthy of remark that (with one possible 

 -exception) the whole of the species of Trichoptera are peculiar to 

 the islands, although belonging to familiar European genera, and 

 that they all inhabit running water in the larval stage." 



The Hemiptera of the Atlantic Islands likewise follow the pre- 

 ceding orders in their general relationship ; but a few cases of distri- 

 bution are deserving of notice, in so far as they throw light on the 

 question of a former Atlantic continent. The genus Noualhieria is 

 confined to the Canary Islands, with two species. Its nearest allies, 

 Ilarniothania^ Sisammes, and Erlacda^ occur in Algeria, Guatemala, 

 and Chili, respectively. Velia maderensis, of Madeira, belongs to a 

 genus confined to Africa, southern Europe, and South America. 

 Erachysteles has two species in Madeira, two in Europe, and one in the 

 West Indies. We can trace the relationship between European or 

 Atlantic Island and American forms in many other cases; but the genera, 

 as a rule, are widespread, and are found on other continents as well. 



