generations, but in a few days their colour changes from a green to a
yellow, which is gradually converted into an orange before they come to
their full growth; they differ also in another respect from those which
occur in summer, for all these yellow females are without wings. The
male insects are, however, still more remarkable, their outward
appearance readily distinguishing them from this and all other
generations. When first produced, they are not of a green colour like
the rest, but of a reddish brown, and have afterwards a dark line along
the back; they come to their full growth in about three weeks, and then
cast off their last covering, the whole insect being after this of a
bright yellow colour, the wings only excepted; but after this change to
a deeper yellow, and in a very few hours to a dark brown, if we except
the body, which is something lighter coloured, and has a reddish cast.
The males no sooner come to maturity than they copulate with the
females, who in a day or two after their intercourse with the males lay
their eggs, generally near the buds. Where there are a number crowded
together, they of course interfere with each other, in which case they
will frequently deposit their eggs on other parts of the branches. It is
highly probable that the aphides derive considerable advantages by
living in society; the reiterated punctures of a great number of them
may attract a larger quantity of nutritious juices to that part of the
tree or plant where they have taken up their abode.
The aphides are very injurious to trees and vegetables of almost every
kind; the species is so numerous, and all endued with so much fertility,
that if they were not destroyed by a numerous host of enemies, the
leaves, the branches, and the stem of every plant would be covered with
them. On almost every leaf inhabited by aphides, a small worm is to be
found, that feeds not upon the leaves, but upon these insects, devouring
them with incredible rapacity: Reaumur supplied a single worm with above
one-hundred aphides, every one of which it devoured in less than three
hours. Indeed myriads of insects seem to be produced for no other
purpose than to destroy them.
OF THE APIS OR BEE.
The bee belongs to the hymenoptera order, the mouth is furnished with
two jaws, and a proboscis protected by a double sheath, see Fig. 3.
Plate XIII. They have four wings; when these are at rest, the two
foremost cover those behind. There is a sting in the tail of the working
and female bee. Of the bee kind fifty-five species are enumerated by
Linnæus. Our present observations are confined to the common or domestic
bee.
In the natural history of insects new objects of surprize are
continually rising before the observer: however singular the preceding
account of the production of the aphides may appear, that of bees is not
less so. This little republic has at all times gained universal esteem
and admiration; and, though they have attracted the attention of the
most ingenious and laborious inquirers into nature, yet the mode of
propagating their species seems to have baffled the ingenuity of ages,
and rendered all attempts to discover it abortive; even the labours and
scrupulous attention of Swammerdam were unsuccessful. He spent one month
entirely in examining, describing, and representing their intestines;
and many months on other parts; employing whole days in making
observations, and whole nights in registering them, till at last he
brought his treatise of bees to the wished for perfection; a work which,
from the commencement of natural history to our own times, has not its
equal. Reaumur, however, thought he had in some measure removed the
veil, and explained their manner of generating: he supposes the queen
bee to be the only female in the hive, and the mother of the next
generation; that the drones are the males, by which she is fecundated,
and that the working bees, or those that collect wax on the flowers,
that knead it, and form from it the combs and cells, which they
afterwards fill with honey, are of neither sex. The queen bee is known
by its size, being generally much larger than the working bee or the
drone.
M. Schirach, a German naturalist, affirms that all the common bees are
females in disguise, in which the organs that distinguish the sex, and
particularly the ovaria, are obliterated, or at least from their extreme
minuteness have escaped the observer’s eye; that every one of these
bees, in the earlier period of its existence, is capable of becoming a
queen bee, if the whole community should think it proper to nurse it in
a particular manner, and raise it to that rank: in short, that the queen
bee lays only two kinds of eggs, those that are to produce the drones,
and those from which the working bees are to proceed. Schirach made his
experiments not only in the early spring months, but even as late as
November. He cut off from an old hive a piece of the brood-comb, taking
care that it contained worms which had been hatched about three days. He
fixed this in an empty hive, together with a piece of honey-comb, for
food to his bees, and then introduced a number of common bees into the
hive. As soon as these found themselves deprived of their queen and
their liberty, a dreadful uproar took place, which lasted for the space
of twenty-four hours. On the cessation of this tumult, they betook
themselves to work, first proceeding to the construction of a royal
cell, and then taking the proper methods for feeding and hatching the
brood inclosed with them; sometimes even on the second day the
foundation of one or more royal cells were to be perceived; the view of
which furnished certain indications that they had elected one of the
inclosed worms to the sovereignty. The bees may now be left at liberty.
The final result of these experiments is, that the colony of working
bees being thus shut up with a morsel of brood-comb, not only hatch, but
at the end of eighteen or twenty days produce from thence one or two
queens, to all appearance proceeding from worms of the common sort,
converted by them into a queen merely because they wanted one.[82] From
experiments of the same kind, varied and often repeated, Schirach
concludes that all the common working bees were originally of the female
sex; but that if they are not fed, lodged, and brought up in a
particular manner while they are in the larva state, their organs are
not developed; and that it is to this circumstance attending the
bringing up the queen, that the extension of the female organs is
effected, and the difference in her form and size produced.
[82] Schirach Histoire Naturelle des Abeilles.
Mr. Debraw has carried the subject further, by discovering the
impregnation of the eggs by the males, and the difference of the size
among the drones or males; though indeed this last circumstance was not
unknown to Mess. Maraldi and Reaumur. Mr. Debraw watched the glass hives
with indefatigable attention, from the moment the bees, among which he
took care there should be a large number of drones, were put into them,
to the time of the queen’s laying her eggs, which generally happens on
the fourth or fifth day; he observed, that on the first or second day,
always before the third from the time the eggs are placed in the cells,
a great number of bees, fastening themselves to one another, hung down
in the form of a curtain, from the top to the bottom of the hive; they
had done the same at the time the queen deposited her eggs, an operation
which seems contrived on purpose to conceal what is transacting;
however, through some parts of this veil he was enabled to see some of
the bees inserting the posterior part of their bodies each into a cell,
and sinking into it, but continuing there only a little while. When they
had retired, it was easy to discover a whitish liquor left in the angle
of the basis of each cell, which contained an egg. In a day or two this
liquor was absorbed into the embryo, which on the fourth day assumes its
worm or larva state, to which the working bees bring a little honey for
nourishment, during the first eight or ten days after its birth. When
the bees find the worm has attained its full growth, they leave off
bringing it food, they know it has no more need of it; they have still,
however, another service to pay it, in which they never fail; it is that
of shutting it up in its cell, where the larva is inclosed for eight or
ten days: here a further change takes place; the larva, which was
heretofore idle, now begins to work, and lines its cell with fine silk,
while the working bee incloses it exteriorly with a wax covering. The
concealed larva then voids its excrement, quits its skin, and assumes
the pupa; at the end of some days the young bee acquires sufficient
strength to quit the slender covering of the pupa, tears the wax
covering of its cell, and proceeds a perfect insect.
To prove further that the eggs are fecundated by the males, and that
their presence is necessary at the time of breeding, Mr. Debraw made the
following experiments. They consist in leaving in a hive the queen, with
only the common or working bees, without any drones, to see whether the
eggs she laid would be prolific. To this end he took a swarm, and shook
all the bees into a tub of water, leaving them there till they were
quite senseless; by which means he could distinguish the drones without
any danger of being stung: he then restored the queen and working bees
to their former state, by spreading them on a brown paper in the sun;
after this he replaced them in a glass hive, where they soon began to
work as usual. The queen laid eggs, which, to his great surprize, were
impregnated, for he imagined he had separated all the drones or males,
and therefore omitted watching them; at the end of twenty days he found
several of his eggs had, in the usual course of changes, produced bees,
while some had withered away, and others were covered with honey. Hence
he inferred, that some of the males had escaped his notice, and
impregnated part of the eggs. To convince himself of this, he took away
all the brood-comb that was in the hive, in order to oblige the bees to
provide a fresh quantity, being determined to watch narrowly their
motions after new eggs should be laid in the cells. On the second day
after the eggs were deposited, he perceived the same operation that was
mentioned before, namely, that of the bees hanging down in the form of a
curtain, while others thrust the posterior part of their bodies into the
cells. He then introduced his hand into the hive, broke off a piece of
the comb, in which there were two of these insects; he found in neither
of them any sting, a circumstance peculiar to the drones; upon
dissection, with the assistance of a microscope, he discovered the four
cylindrical bodies which contain the glutinous liquor of a whitish
colour, as observed by Maraldi in the large drones. He was therefore now
under the necessity of repeating his experiments, in destroying the
males, and even those that might be suspected to be such. He once more
immersed the same bees in water, and when they appeared in a senseless
state, he gently pressed every one, in order to distinguish those armed
with stings from those which had none, and which of course he supposed
to be males: of these last he found fifty-seven, and replaced the swarm
in a glass hive, where they immediately applied again to the work of
making cells, and on the fourth or fifth day, very early in the morning,
he had the pleasure to see the queen bee deposit her eggs in those
cells: he continued watching most part of the ensuing days, but could
discover nothing of what he had seen before.
The eggs, after the fourth day, instead of changing in the manner of
caterpillars, were found in the same state they were in the first day,
except that some were covered with honey. A singular event happened the
next day, about noon; all the bees left their own hive, and were seen
attempting to get into a neighbouring one, on the stool of which the
queen was found dead, being no doubt slain in the engagement. This event
seems to have arisen from the great desire of perpetuating their
species, and to which end the concurrence of the males seems so
absolutely necessary; it made them desert their habitations, where no
males were left, in order to fix a residence in a new one, in which
there was a good stock of them. To be further satisfied, Mr. Debraw took
the brood-comb, which had not been impregnated, and divided it into two
parts; one he placed under a glass bell, No. 1, with honey-comb for the
bees food, taking care to leave a queen, but no drones, among the bees
confined in it; the other piece of the brood-comb he placed under
another glass bell, No. 2, with a few drones, a queen, and a
proportionable number of common bees. The result was, that in the glass,
No. 1, there was no impregnation, the eggs remaining in the same state
they were in when put into the glass; and on giving the bees their
liberty on the seventh day, they all flew away as was found to be the
case in the former experiment; whereas in the glass, No. 2, the very day
after the bees had been put into it, the eggs were impregnated by the
drones, and the bees did not leave their hive on receiving their
liberty.
The editor of the Cyclopædia says, that the small drones are all dead
before the end of May, when the larger species appear, and supersede
their use; and that it is not without reason that a modern author
suggests, that a small number of drones are reserved to supply the
necessities of the ensuing year; but that they are very little, if any,
larger than the common bee.
It does not enter into our plan to notice further in this place the
wonders of this little society. A bee-hive is certainly one of the
finest objects that can offer itself to the eyes of the beholder. It is
not easy to be weary of contemplating those workshops, where thousands
of labourers are constantly engaged in different employments.[83]
[83] The remarks made by the late Mr. Hunter on the experiments of
Messrs. Schirach and Debraw, in my opinion, merit the attention of the
reader; they are contained in his “Observations on Bees,” comprizing a
variety of information respecting the history and œconomy of those
curious insects. This ingenious and interesting account is inserted in
the Philosophical Transactions for the year 1792, page 128-195. I
cannot altogether subscribe to his opinion relative to the minuteness
and prolixity of Swammerdam. EDIT.
OF THE EGGS OF INSECTS.
The eggs are contained and arranged in the body of the insect, in
vessels which vary in number and figure in different species; the same
variety is found in the eggs themselves: some are round, others oval,
some cylindrical, and others nearly square; the shells of some are hard
and smooth, while others are soft and flexible. It is a general rule,
that eggs do not increase in size after they are laid; among insects, we
find however an exception to this; the eggs of the tenthredo of Linnæus
increase after they are laid, but their shell is soft and membranaceous.
The eggs of insects differ in their colours; some may be found of almost
every shade, of yellow, green, brown, and even black. The eggs of the
lion puceron,[84] hemerobius, Lin. are very singular objects, and cannot
have escaped the eye of any person who is conversant among the insects
which live on trees; though of the many who have seen them, few, if any,
have found what they really were. It is common to see on the leaves and
pedicles of the leaves of the plumb-tree, and several other trees, as
also on their young branches, a number of long and slender filaments,
running out to about an inch in length; ten or twelve of these are
usually seen placed near one another, and a vast number of these
clusters are found on the same tree; each of these filaments is
terminated by a sort of swelling or tubercle of the shape of an egg.
They have generally been supposed to be of vegetable origin, and that
they were a sort of parasitical plant growing out of others. There is a
time when these egg-like balls are found open at the ends; in this state
they very much resemble flowers, and have been figured as such by some
authors, though they are only the shells of the eggs out of which the
young animals have escaped after being hatched. If these eggs be
examined by a microscope, a worm may be discovered in them; or they may
be put into a box, in which, in due time, they will produce an insect,
which, when viewed with a microscope, will be found to be the true lion
puceron.
[84] Reaumur Hist. de Insectes, vol. xi. p. 142.
Divine Providence instructs the insects, by a lower species of
perception, to deposit their eggs not only in safety from their numerous
enemies, but also in situations where a sufficient quantity of food is
on the spot to support and nourish the larva immediately on breaking the
shell. Some deposit their eggs in the oak leaf, producing there the red
gall; others choose the leaf of the poplar, which swells into a red node
or bladder; to a similar cause we must attribute the red knob which is
often seen on the willow leaf, and the three pointed protuberances upon
the termination of the juniper branches. The leaves of the veronica and
cerastium are drawn into a globular head by the eggs of an insect lodged
therein. The phalæna neustria glues its eggs with great symmetry and
propriety round the smaller branches of trees. Fig. 1. Plate X.
represents a magnified view of the nest of eggs taken off the tree after
the caterpillar had eaten its way through them; the strong ground-work
of gum, by which they are connected and bound together, is very visible
in many places; they strengthen this connection further, by filling up
all the intervening space between the eggs with a very tenacious
substance. These eggs are crustaceous, and similar to those of the hen;
Fig. 2 represents the natural size. Fig. 3 is a magnified vertical
section of the eggs, shewing their oval shape; Fig. 4 the natural size.
Fig. 5 is an horizontal section through the middle of the egg, and Fig.
6 the same not magnified. It is not easy to describe the beauty of these
objects, when viewed in the lucernal microscope; the regularity with
which they are placed, the delicacy of their texture, the beautiful and
ever-varying colours which they present to the eye, give the spectator a
high degree of rational delight.
In the Lapland Alps there is a fly covered with a downy hair, called the
rhen-deer gad-fly, oestrus tarandi, Linn. it hovers all day over these
animals, whose legs tremble under them; they prick up their ears, and
flee to the mountains covered with ice and snow to escape from a little
hovering fly, but generally in vain, for the insect but too soon finds
an opportunity to lodge its egg in the back of the deer; the worm
hatched from this egg perforates the skin, and remains under it during
the whole winter: in the following year it becomes a fly. The oestrus
bovis is an equal terror to oxen; the hippobosca equina, to horses;
oestrus ovis,[85] to the sheep, &c.
[85] Oestrus ovis in naso sive sinu frontis animalium rumenantium.
Linn.
The gnat, the ephemera, the phryganea, the libellula, hover over the
water all day to drop their eggs, which are hatched in the water, and
continue there all the time they are in the larva form. The mass formed
by the gnat resembles a little vessel set afloat by the insect; each egg
is in the form of a keel, these are curiously connected together. The
gnat lays but one egg at a time, which she deposits on the water in a
very ingenious and simple manner; she stretches her legs out, and
crosses them, thus forming an angle to receive and hold the first egg; a
second egg is soon placed next the first; then a third, and so on, till
the base is capable of supporting itself; these, as they come to
maturity, sink deeper. The spawn of this insect is sometimes above an
inch long, and one-eighth of an inch in diameter, and tied by a little
stem or stalk to some stick or stone. Sometimes they are laid in a
single, sometimes in a double spiral line; sometimes transversely. Many
moths cover their offspring with a thick bed of hair, which they gather
from their own body; while others cover them with a glutinous
composition, which, when hard, protects them from moisture, rain, and
cold. The gall-flies, it has been observed, know how to open the nerves
of the leaves, to deposit thus their eggs in a place which afterwards
serves them for a lodging and a magazine of food. The solitary bees and
wasps prepare an habitation for their little ones in the earth, placing
there a proper quantity of food for them, when they proceed from the
egg. The voracious and cruel spider is attentive and careful of its
eggs; the wolf spider carries them on its back in a little bag formed of
its silk, it cannot be separated from them but by violence, and exhibits
the most marked signs of uneasiness when deprived of them: a
circumstance the more remarkable, as they love to destroy each other,
and even carry on their courtships with a diffidence and caution unknown
in any other species of animals. The history of bees and wasps, and
their care and attention to their offspring, is so well known, that I
may with propriety pass it over here, and proceed just to notice the
industrious ant, whose paternal affection and care is not so well known.
They are not satisfied with placing their eggs in situations made on
purpose, and to raise or rear them till they come to the nymph or pupa
state, but they even extend their care to the pupæ themselves, removing
them from their nest to the surface of the earth, whenever the weather
is fine, that they may receive the benignant influence of the sun,
carrying them back again as soon as the air begins to grow cold. If any
accident disturb their nest, and disperse the pupæ, they manifest the
greatest signs of distress, seeking those which are lost and scattered,
placing them in some sheltered place while they repair the nest, when
they again transport them to it.[86] Many other curious particulars
might be related relative to this industrious insect; as their uniting
together in scooping out earth, the conveyance of materials for the
construction of their nests, and the curious structure of the nest
itself, which, though it appears piled up at random, will be found, on
stricter examination, to be a work of art and design, with other
circumstances which are too long to be enumerated here.
[86] Lessers Theologie des Insectes, tom. 1, p. 143.
The fecundity of insects exceeds in an astonishing degree that of all
the productions of nature; the vegetables which cover the surface of the
earth bear no proportion to their multitudes, every plant supporting a
number often of scarce perceptible creatures: of the fatal effects of
their prodigious multiplication, our fruit trees, &c. are too frequently
a deplorable testimony. On the continent whole provinces sometimes
languish in consequence of the dreadful havoc made by them.
Reaumur calculated the fecundity of the queen bee as follows: he found
that she laid in the two months of March and April 12,000 eggs, so that
the swarm which left the hive in May consisted of near 12,000 bees, all
produced from one mother: but this calculation falls short of that which
was made by Leeuwenhoek on a fly, whose larva feeds on flesh, putrid
carcases, &c. which multiply prodigiously, and that in a short space of
time. One of these laid 144 eggs, from which he got as many flies in the
first month; so that, supposing one-half of these to be females, in the
third month we shall have 746,496, all produced in three months from one
fly.