Origin of Species Variorum

→ The occasional habit of birds laying 1859 1860 1861 1866 1869

Various birds, as has already been remarked, occasionally lay 1872

→ other birds' nests, either of the same or of distinct species, 1866

other birds' nests, either of the same or of a distinct species, 1859 1861

other birds nests, either of the same or of a distinct species, 1860

other birds nests, either of the same or of distinct species, 1869

the nests of other birds. This habit 1872

→ this perhaps explains the origin of a 1859 1860 1861 1866 1869

throws some light on the 1872

→ allied group of 1859 1860 1861 1866

nearest allied group, that of 1869

OMIT 1872

→ For several hen ostriches 1866 1869

For several hen ostriches, at least in the case of the American species, 1859 1860 1861

In this family several hen-birds 1872

→ case of the 1859 1860 1861 1866 1869

OMIT 1872

→ has 1859 1860 1861 1866 1869

as in the case of the Molothrus bonariensis, has 1872

→ kinds. 1859 1860 1861 1866

kinds of bees. 1869 1872

→ be necessary 1859 1860 1861 1866

have been indispensable 1869 1872

→ likewise, of Sphegidæ (wasp-like insects) are 1859 1860 1861 1866 1869

of Sphegidæ (wasp-like insects) are likewise 1872

→ on other species; 1859 1860 1861 1866

in the same manner on other species; 1869

OMIT 1872

→ to feed on, 1859 1860 1861 1866

OMIT 1869 1872

→ the supposed case 1859 1860 1861 1866 1869

that 1872

→ cuckoo, 1859 1860 1861 1866 1869

Molothrus or cuckoo, 1872

→The occasional habit of birds laying their eggs in →other birds' nests, either of the same or of distinct species, is not very uncommon with the

Gallinaceæ

Gallinaceæ,

Gallinaceæ;

and →this perhaps explains the origin of a singular instinct

the →allied group of

ostrich.

ostriches.

→For several hen ostriches unite and lay first a few eggs in one nest and then in another; and these are hatched by the males. This instinct may probably be accounted for by the fact of the

hens

here

laying a large number of

eggs;

eggs,

but, as

with

the →case of the cuckoo, at intervals of two or three days.

The

This

instinct, however, of the American

ostrich,

ostrich

→has not as yet been perfected; for a surprising number of eggs lie strewed over the plains, so that in one

days

day's

hunting I picked up no less than twenty lost and wasted eggs.

Many bees are parasitic, and

regularly

always

lay their eggs in the nests of

~~bees of~~

bees of

other →kinds. This case is more remarkable than that of the cuckoo; for these bees have not only

had their

their

instincts but their structure modified in accordance with their parasitic habits; for they do not possess the pollen-collecting apparatus which would →be necessary if they had

stored

store

up food

food

for their own young. Some

species

species,

→likewise, of Sphegidæ (wasp-like insects) are

parasitic;

parasitic

→on other species; and M. Fabre has lately shown good reason for believing

that

that,

although the Tachytes nigra generally makes its own burrow and stores it with paralysed prey for its own

larvæ,

larvæ

→to feed on, yet

that

that,

when this insect finds a burrow already made and stored by another sphex, it takes advantage of the prize, and becomes for the occasion parasitic. In this case, as with →the supposed case of the →cuckoo, I can see no difficulty in natural selection making an occasional habit permanent, if of advantage to the species, and if the insect whose nest and stored food are

~~thus~~

thus

feloniously

appropriated

appropriated,

be not thus exterminated.