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that I think it far from improbaMe that it is a fixed 

 insular state of that insect. Deucalion, also, may be 

 quoted in support of this twofold hypothesis, of the 

 direction, and the slowness, of the former migratory 

 movements. It is an apterous genus, and of eminently 

 sluggish habits ; and what is the consequence ? — we have 

 a very remarkable species (the D. oceanicum, WoU.) on 

 one of the rocks of the Salvages, whilst another (the 

 D. Desertarum, WoU.) has been isolated on the two 

 southernmost islands of the Madeiran Group ; and of so 

 sedentary a nature is this last, that, although physically 

 unimpeded, it has not, even to this day, overrun the 

 diminutive areas on which, when the surrounding region 

 was submerged, it was originally saved from destruction. 

 So strongly indeed was this fact impressed upon me, 

 when I first detected it, that I shall perhaps be excused 

 for recapitulating in extenso the few reflexions which 

 then suggested themselves to my mind. " There is no 

 genus, perhaps, throughout all the Madeiran Coleoptera, 

 more truly indigenous than Deucalion. Confined appa- 

 rently, so far as these islands are concerned, to the 

 remote and almost inaccessible ridges of the two south- 

 em Dezertas, it would seem to bid defiance to the most 

 enthusiastic adventurer who would scale those dangerous 

 heights. Its excessive rarity, moreover, even when the 

 localities are attained, must ever impart to it a peculiar 

 value in the eyes of a naturalist ; whilst its anomalous 

 structure and sedentary* mode of life give it an addi- 



* " When we consider indeed the apterous nature of Deucalion, 



