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diminish the stature of the insect tribes, or else to neu- 

 tralize their power of flight ; but that, in the latter case, 

 the creatures, when thus despoiled of a function, do, on the 

 contrary (instead of deteriorating in size), often receive 

 a compensation for their loss by an actual increase in 

 their bulk. The common Brady cellus fulvus, Mshm, is 

 another instance in point. From its occurrence in the 

 almost inaccessible districts of the Madeiran group, far 

 removed from cultivation, I am inclined to refer its entry 

 into this southern region to that remote period when a 

 connective land offered a natural passage to wanderers 

 from the north. Hence our first stipulation, that of 

 sufficient time, is satisfied ; and what is the result ? The 

 insect is a trifle more robust than its ordinary European 

 representatives, and it is invariably apterous. The Ca- 

 lathus fuscus, Fabr., is also, as is clear from its special 

 attachment to the mountain tops, strictly indigenous in 

 Madeira (that is to say, it must have arrived there 

 during the migratory epoch) ; and the consequence is, 

 that, although usually winged in our own country, it is 

 permanently subapterous in that island. I think it far 

 from unlikely that the Dromius negrita, Woll., may be 

 the ultimate phasis (from isolation) of the common D. 

 glabratus, Dufts., from which it may be distinguished 

 by its somewhat larger bulk, more robust head and pro- 

 thorax, and by the obsoleteness of its wings. True it is, 

 that the latter species flourishes alongside it in Madeira; 

 but, like the Vanessa Atalanta (when considered with 

 respect to the V. Callirhoe), may it not be of more recent 



