692 Mr. T. D. A. Cockerell on the 



subsp. maderensis. In the small Nordeste Island, off Porto 

 Santo, Helops /z<ci/iw^z^5,Wollaston,bas been modified, formiug 

 a subspecies which I have described as maritimus ^. 



At this point it is of interest to compare the situation in 

 the Hawaiian Islands, where the number of flightless beetles 

 is also a striking feature. Thus Perkins remarks that of 

 the endemic Carabidse 184 species are flightless, only 20 fully 

 winged ; furthermore, ^' Nearly all the flightless endemic 

 insects are inhabitants of the forest, or if they frequent 

 exposed situations like some of the Carabidse, they are closely 

 related to species that frequent thick forests, and are equally 

 flightless^' t- Accordingly, Perkins is decidedly of opinion 

 that Darwin's theory of selection, as given above, does not 

 apply to these Hawaiian insects, but he offers the still less 

 acceptable theory of the effects of disuse. If we discard 

 both theories, there remains the selection by sea already 

 suggested. To this may be added the general fact that 

 mutations are more often in the direction of loss or reduction 

 of parts than the reverse. Such mutations, occurring in the 

 wings, would be much less inimical on remote islands than 

 on continents, owing to the smaller number of natural 

 enemies. They would also, by preventing active movement, 

 tend to prevent free intercrossing between members of the 

 species, so that the isolated colonies might exhibit recessive 

 features with diminished danger of swamping by inter- 

 crossing. These are very general considerations, and we do 

 not know their actual significance. 



In the main island of Madeira, it is difficult to suppose 

 that Coleoptera are in any particular danger of being blown 

 into the sea. Gales are not infrequent, to be sure, but their 

 force, is usually felt as they come from the sea, blowing 

 inland. The high precipitous mountains shelter the coasts 

 from winds sweeping across the island. Thus the Bay of 

 Funchal is an admirable shelter for ships when the wind 

 blows from the north, but if (as sometimes happens) it 

 suddenly veers round, they have the greatest difficulty in 

 avoiding disaster. A wreck occurred in this manner while 

 I was in Madeira. This would not apply to the small and 

 barren islands, and it must be said that some of these are 

 wind-swept in such a manner that flying insects might well 

 get lost, unless strong on the wing. Observation shows that 

 beetles abound on these islets, but practically all living 



* Trans. Ent. Soc. London, 1921, Proc. pp. Ivii-lix, where for Itheo 

 read Illieo, for Nardeste, Nordeste, and (ov jyartosanctanus, portosanctaims. 

 t ' Fauna llawaiiensis,' Introduction, vol. i. part vi. pi. 1. 



