Origin of Species Variorum

→ OMIT 1872

case of the 1859 1860 1861 1866 1869

→ as in the case of the Molothrus bonariensis, has 1872

has 1859 1860 1861 1866 1869

→ kinds of bees. 1869 1872

kinds. 1859 1860 1861 1866

→ have been indispensable 1869 1872

be necessary 1859 1860 1861 1866

→ of Sphegidæ (wasp-like insects) are likewise 1872

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

→ OMIT 1872

on other species; 1859 1860 1861 1866

in the same manner on other species; 1869

→ OMIT 1869 1872

to feed on, 1859 1860 1861 1866

→ that 1872

the supposed case 1859 1860 1861 1866 1869

→ Molothrus or cuckoo, 1872

cuckoo, 1859 1860 1861 1866 1869

→ work of any kind, and the workers or sterile females, though most energetic and courageous in capturing slaves, do no other work. 1861 1866 1869 1872

work. 1859 1860

↑ 1 blocks not present in 1861 1866 1869 1872; present in 1859 1860

The workers or sterile females, though most energetic and courageous in capturing slaves, do no other work.

but, as

with

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

This

The

instinct, however, of the American

ostrich

ostrich,

→as in the case of the Molothrus bonariensis, 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

always

regularly

lay their eggs in the nests of

bees of

....

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

their

had their

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

....

store

stored

food

up food

for their own young. Some

species,

species

→of Sphegidæ (wasp-like insects) are likewise

parasitic

parasitic;

→OMIT 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,

→OMIT 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 →that of the →Molothrus or 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

....

feloniously

appropriated

appropriated,

be not thus exterminated.

Slave-making instinct .—

This remarkable instinct was first discovered in the Formica (Polyerges) rufescens by Pierre Huber, a better observer even than his celebrated father. This ant is absolutely dependent on its slaves; without their aid, the species would certainly become extinct in a single year. The males and fertile females do no →work of any kind, and the workers or sterile females, though most energetic and courageous in capturing slaves, do no other work. ↑ They are incapable of making their own nests, or of feeding their own larvæ. When the old nest is found inconvenient, and they have to migrate, it is the slaves which determine the migration, and actually carry their masters in their jaws. So utterly helpless are the masters, that when Huber shut up thirty of them without a slave, but with plenty of the food which they like best, and with their

larvæ

own larvæ

and pupæ to stimulate them to work, they did nothing; they could not even feed themselves, and many perished of hunger. Huber then introduced a single slave (F. fusca), and she instantly set to work, fed and saved the survivors; made some cells and tended the larvæ, and put all to rights. What can be more extraordinary than these well-ascertained facts? If we had not known of any other slave-making ant, it would have been hopeless to

have

....

speculated

speculate

how so wonderful an instinct could have been