210 ZOOLOGICAL GEOGRAPHY. [part in. 



any other, and its comparatively remote situation, combined with 

 its luxuriant vegetation, have been favourable to the develop- 

 ment and increase of the peculiar forms which characterize all 

 the Atlantic islands in a more or less marked decree. A con- 



O 



sideration of some of its peculiarities will, therefore, best serve 

 to show the bearing of the facts presented by the insect fauna of 

 the Atlantic islands, on the general laws of distribution. The 

 711 species of beetles now known from the Madeira group, 

 belong to 236 genera ; and no less than 44 of these genera are 

 not European but are peculiar to the Atlantic islands. Most of 

 them are, however, closely allied to European genera, of which 

 they are evidently modifications. A most curious general feature 

 presented by the Madeiran beetles, is the total absence of many 

 whole families and large genera abundant in South Europe. 

 Such are the Cicindelidte, or tiger beetles ; the Melolonthida?, or 

 chafers ; the Cetoniidce, or rose-chafers ; the Eumolpida^ and 

 Galerucidse, large families of Phytophagous, or leaf-eating beetles ; 

 and also the extensive groups of Elateridse and Buprestidte, 

 which are each represented by but one minute species. Of 

 extensive genera abundant in South Europe, but wholly absent 

 in Madeira, are Carahus, RMzotrogus, Lampyrw, and other 

 genera of Malacoderms ; Otiorhynchus, Bracliycerus, and 20 

 other genera of Curculionidte, comprising more than 300 South 

 European and N"orth African species ; Pimclia, Tentyra, Blaps, 

 and 18 other genera of Heteromera, comprising about 550 species 

 in South Europe and North Africa ; and Timarcha, containing 

 44 South European and North African species. 



Another most remarkable feature of the Madeiran Coleoptera 

 is the unusual prevalence of apterous or wingless insects. This 

 is especially the case with groups which are confined to the 

 Atlantic islands, many of which consist wholly of wingless 

 species ; but it also affects the others, no less than twenty-two 

 genera which are usually or sometimes winged in Europe, having 

 only wingless species in Madeira ; and even the same species 

 which is winged in Europe becomes, in at least three cases, 

 wingless in Madeira,-'without any other perceptible change having 

 taken phu'c. But there is another most curious fact noticed by 



