with six legs, two long antennæ, and four eyes. These larvæ are hatched in the nests of bees; and when the male-bees emerge from their burrows, in the spring, which they do before the females, the larvæ spring on them, and afterwards crawl on to the females whilst paired with the males. As soon as the female bee deposits her eggs on the surface of the honey stored in the cells, the larvæ of the Sitaris leap on the eggs and devour them. Afterwards they undergo a complete change; their eyes disappear; their legs and antennæ become rudimentary, and they feed on honey; so that they now more closely resemble the ordinary larvæ of insects; ultimately they undergo a further transformation, and finally emerge as the perfect beetle. ↑5 blocks not present in 1859 1860 1861 1872; present in 1866 1869 | Fritz Müller, who has recently discussed this whole
subject with much ability, goes so far as to
believe
that the progenitor of all insects probably
resembled an adult insect, and that the caterpillar or maggot,
and
cocoon or pupal stages, have subsequently been acquired; but from this view many naturalists, for instance Sir J. Lubbock, who has likewise recently discussed this subject, would, it is probable, dissent.
That certain unusual stages in the metamorphoses of insects have arisen from
adaptations
to peculiar habits of life
can
hardly be doubted:
thus the first larval form of a certain beetle, the Sitaris, as described by M. Fabre, is a minute, active
insect, furnished with six legs, two long antennæ, and four eyes.
These larvæ are hatched in the nest
of a
bee;
and when the male-bees emerge in the spring
from their burrows,
which
they
do
before the females, the larvæ spring on them, and afterwards take an early and natural opportunity of crawling on to the female-bees.
When the latter
lay their eggs,
one in each cell,
on the surface of the contained
honey,
the larva
leaps
on the egg
and devours
it.
It then
undergoes
a complete change; its
eyes disappear; its
legs and antennæ become rudimentary, and it
feeds
on honey; so that it
now more closely resembles
the ordinary larvæ of insects; ultimately it
undergoes
further
transformations,
and finally emerges
as a
perfect beetle.
|
Now, if an insect, undergoing transformations like those of the Sitaris,
were to become were to become 1869 1872 |
had been 1866 |
the progenitor of
a
whole
new
class of insects,
the the 1872 | the general 1866 | their 1869 |
course of
development development 1872 | development, 1866 | develop- ment 1869 |
of the new class would be of the new class would be 1872 |
and especially that of the first larval stage, would probably have been 1866 |
would probably be 1869 |
widely different from
that
of our existing insects; and of our existing insects; and 1872 |
is actually the case; and it should be especially noted that 1866 |
it now is; and 1869 |
the first larval stage
certainly would not certainly would not 1869 1872 |
would not have 1866 |
represent represent 1869 1872 | represented 1866 |
the
former former 1869 1872 | adult 1866 |
condition of any
adult and ancient form. adult and ancient form. 1872 |
insect. 1866 |
adult and ancient insect. 1869 |
|
|
On the other hand it is
highly probable highly probable 1869 1872 | probable 1866 |
that with many
....... 1869 1872 | groups of 1866 |
animals the
embryonic or embryonic or 1869 1872 | earlier 1866 |
larval stages
..
show us, more or less completely, the
condition condition 1872 | form 1866 | state 1869 |
of the
...OMIT 1869 1872 |
ancient and adult 1866 |
progenitor of the whole
group in its adult state. group in its adult state. 1872 |
group. 1866 |
group in its adult condition. 1869 |
In the
great great 1869 1872 | enormous 1866 |
class of the Crustacea, forms wonderfully distinct from each other,
namely, namely, 1869 1872 | as the 1866 |
suctorial parasites, cirripedes, entomostraca, and even the malacostraca, appear
at first as larvæ under the at first as larvæ under the 1869 1872 |
in their first larval state under a similar 1866 |
nauplius-form; nauplius-form; 1869 1872 | nauplius form; 1866 |
and as these larvæ
live
and
feed
in the open sea, and are not adapted for any peculiar habits of life, and from other reasons assigned by Fritz
Müller, Müller, 1872 | Müller, 1866 1869 |
it is probable that
at some very remote period an at some very remote period an 1872 |
an 1866 1869 |
independent adult animal, resembling the
Nauplius, Nauplius, 1872 | nauplius, 1866 1869 |
....... 1869 1872 | formerly 1866 |
existed, existed, 1872 | existed 1866 1869 |
and and 1872 |
at a remote period, and has 1866 |
at some very remote period, and 1869 |
subsequently produced,
...OMIT 1869 1872 |
through long-continued modification 1866 |
along several divergent lines of descent, the
....... 1872 | several 1866 1869 |
above-named great Crustacean groups. So again it is probable, from what we know of the embryos of mammals, birds, fishes, and reptiles, that
these animals these animals 1869 1872 |
all the members in these four great classes 1866 |
are the modified descendants of some
..
ancient progenitor, which was furnished in its adult state with branchiæ,
..
a swim-bladder, four
fin-like fin-like 1872 | simple 1866 1869 |
limbs, and a long
tail,
all fitted all fitted 1869 1872 | fitted 1866 |
for an aquatic life. |
|
As all the organic beings, extinct and recent, which have ever
lived, lived, 1869 1872 | lived 1859 1860 1861 1866 |
can be arranged within a few great classes; can be arranged within a few great classes; 1869 1872 |
on this earth have to be classed together, 1859 1860 1861 |
on this earth, have to be classed together, 1866 |
and as all
within each class have, according to our theory, within each class have, according to our theory, 1872 |
have 1859 1860 1861 1866 |
within each class have, according to our theory, formerly 1869 |
been connected
together by fine together by fine 1869 1872 |
by the finest 1859 1860 |
by fine 1861 1866 |
gradations, the best,
and, and, 1869 1872 | or indeed, 1859 1860 1861 | or, 1866 |
if our collections were nearly perfect, the only possible arrangement, would be
genealogical; genealogical; 1861 1866 1869 1872 | genealogical. 1859 1860 |
descent descent 1861 1866 1869 1872 | Descent 1859 1860 |
being
...OMIT 1869 1872 |
on my view 1859 1860 1861 |
on this view 1866 |
the hidden bond of connexion which naturalists have been seeking under the term of the
Natural Natural 1869 1872 | natural 1859 1860 1861 1866 |
System. System. 1869 1872 | system. 1859 1860 1861 1866 |
On this view we can understand how it is that, in the eyes of most
naturalists, naturalists, 1859 1860 1861 1866 1872 | natu- ralists, 1869 |
the structure of the embryo is even more important for classification
|