EVIDENCES FROM MORPHOLOGY 143 
quently we can understand why on this island we should meet with 
such a remarkable dwindling away of wings. 
Similarly, the logger-headed duck of South America can only flap 
along the surface of the water, having its wings considerably reduced 
though less so than the Apieryx of New Zealand. But here the 
interesting fact is that the young birds are able to fly perfectly well. 
Now, in accordance with a general law to be considered in a future 
chapter, the life-history of an individual organism is a kind of con- 
densed recapitulation of the life-history of its species. Consequently, 
we can understand why the little chickens of the logger-headed duck 
are able to fly like all other ducks, while their parents are only able 
to flap along the surface of the water. 
Facts analogous to this reduction of wings in birds which have no 
further use for them, are to be met with also in insects under similar 
circumstances. Thus,-there are on the island of Madeira somewhere 
between 500 and 600 species of beetles, which are in large part peculiar 
to that island, though related to other—and therefore presumably 
parent—species on the neighboring continent. Now, no less than 200 
species—or nearly half the whole number—are so far deficient in | 
wings that they cannot fly. And, if we disregard the species which 
are not peculiar to the island—that is to say, all the species which 
likewise occur on the neighboring continent, and therefore, as evolu- 
tionists conclude, have but recently migrated to the island,—we find 
this very remarkable proportion. There are altogether 29 peculiar 
genera, and out of these no less than 23 have all their species in this 
condition. 
Similar facts have been recently observed by the Rev. A. E. Eaton 
with respect to insects inhabiting Kerguelen Island. All the species 
which he found on the island—viz., a moth, several flies, and numerous 
beetles—he found to be incapable of flight; and therefore, as Wallace 
observes, ‘‘as these insects could hardly have reached the islands in 
a wingless state, even if there were any other known land inhabited 
by them, which there is not, we must assume that, like the Madeiran 
insects, they were originally winged, and lost their power of flight 
because its possession was injurious to them’’—Kerguelen Island 
being “one of the stormiest places on the globe,” and therefore a place 
where insects could rarely afford to fly without incurring the danger 
of being blown out to sea. 
Here is another and perhaps an even more suggestive class of 
facts. 
