Origin of Species Variorum

→ cautious in denying this tendency. 1872

cautious. 1861

cautious in denying such power. 1866 1869

→ Hence it will perhaps be safest to look at 1869 1872

There is not sufficient evidence to induce us to believe that mutilations are ever inherited; and I should prefer explaining 1859

There is not sufficient evidence to induce me to believe that mutilations are ever inherited; and I should prefer explaining 1860

So that it will perhaps be safest to look at 1861 1866

→ not as cases of inherited mutilations, but as due to the 1872

by the long-continued 1859 1860

as due to the long-continued 1861 1866

as due to the 1869

→ long-continued disuse; 1869 1872

disuse in their progenitors; 1859 1860 1861 1866

→ OMIT 1869 1872

the tarsi are almost always lost in 1859 1860 1861 1866

→ are generally found with their tarsi lost, this must happen 1869 1872

they must be lost 1859 1860 1861 1866

→ the tarsi cannot be of much importance or 1869 1872

cannot 1859 1860 1861 1866

→ much 1859 1860 1869 1872

of much importance or be much 1861 1866

→ (but more are now known) inhabiting 1872

inhabiting 1859 1860 1861

(but more are now known) which inhabit 1866 1869

→ that 1872

of the almost entire absence of 1859 1860 1861 1866 1869

→ absolutely require the use of their wings, are here almost entirely absent;— 1872

groups have habits of life almost necessitating frequent flight;— 1859 1860 1861

groups have habits of life almost necessitating frequent flight; — 1866 1869

us →cautious in denying this tendency. →Hence it will perhaps be safest to look at the entire absence of the anterior tarsi in Ateuchus, and their rudimentary condition in some other genera, →not as cases of inherited mutilations, but as due to the effects of →long-continued disuse; for as →OMIT many dung-feeding

beetles,

beetles

→are generally found with their tarsi lost, this must happen early in

life,

life;

and

....

therefore →the tarsi cannot be of much importance or be →much used by these insects.

In some cases we might easily put down to disuse modifications of structure which are wholly, or mainly, due to natural selection. Mr. Wollaston has discovered the remarkable fact that 200

beetles

beetles,

out of the 550 species →(but more are now known) inhabiting

Madeira

Madeira,

are so far deficient in wings that they cannot fly; and

that

that,

of the twenty-nine endemic genera, no less than twenty-three

genera

....

have all their species in this condition! Several

facts,

facts,—

— namely,

namely,

that beetles in many parts of the world are

very

....

frequently blown to sea and perish; that the beetles in Madeira, as observed by Mr. Wollaston, lie much

con-

....

cealed,

concealed,

until the wind lulls and the sun shines; that the proportion of wingless beetles is larger on the exposed

Dezertas

Desertas

than in Madeira itself; and especially the extraordinary fact, so strongly insisted on by Mr. Wollaston, →that certain large groups of beetles, elsewhere excessively numerous,

and

....

which →absolutely require the use of their wings, are here almost entirely absent;— these several considerations

have

....

made

make

me believe that the wingless condition of so many Madeira beetles is mainly due to the action of natural selection,

but

....

combined probably with disuse. For during

thousands of

many

successive generations each individual beetle which flew least, either from its wings having been ever so little less perfectly developed or from indolent habit, will have had the best chance of surviving from not being blown out to sea; and, on the other hand, those beetles which most readily took to flight

will

would

oftenest have been blown to

sea

sea,

and thus

have been

....

destroyed.

The insects in Madeira which are not ground-feeders, and which, as

the

certain

flower-feeding coleoptera and lepidoptera, must habitually use their wings to gain their subsistence, have, as Mr. Wollaston suspects, their wings not at all reduced, but even enlarged. This is quite compatible with the action of natural selection. For when a new insect first arrived on the island, the tendency of natural selection to enlarge or to reduce the wings, would depend on whether a greater number of individuals were saved by successfully battling with the winds, or by giving up the attempt and rarely or never flying. As with mariners shipwrecked near a coast, it would have been better for the good swimmers if they had been able to swim still further, whereas it would have been better for the bad