Water Insects.--Aquaria.
One July afternoon the boys had been fishing, and to seek some shade and
coolness while eating their lunch, they had driven the yacht into a
quiet pool among the reeds, which almost met over them. The water below
them was very clear and still, and as it was only about two feet deep
they could see the bottom quite plainly, and they soon found that it was
well worth a close inspection. The pool was teeming with insect life.
The surface of the water was covered with tiny whirligig beetles, which
were skimming about in mazy, coruscating evolutions.
"Those whirligig beetles," said Dick, "have their eyes made with two
faces--one to look down into the water, and the other to look into the
sky."
"What a lot you have learnt about insects, Dick, in the course of a few
months," said Frank.
[Illustration: METAMORPHOSES OF FLESH-FLY.]
"It is a grand study," said Dick enthusiastically; "and I have worked my
best at it. When one goes hard at a thing it is astonishing how soon one
picks up a lot of knowledge about it. I have read over and over again
about the common insects, or those that are the most noticeable."
"Well, tell us about all those insects we see now."
[Illustration: WATER-BEETLE.]
"Look at those long-legged narrow-bodied flies which are sliding along
over the surface. These are called water-measurers. That oval beetle
which is swimming on its back, and using two legs like oars, is the
water boatman. It fastens on to the head of small fish, and soon kills
them. It lives in the water, but if put on land it can fly. Look at that
brute crawling over the mud, with its lobster-like head. It has sharp
claws and a hollow snout. It lies in wait for its victims, and when it
seizes them it sucks the juice out of them with its beak. It looks only
of a dull brown now, but when its wings are expanded its body is of a
blood red colour, and its tail is forked. It sometimes comes out for a
fly at night."
"And what is the fearfully ugly thing climbing up that reed-stem just
out of the water?"
[Illustration: PUPA OF DRAGON-FLY.]
[Illustration: COMPOUND EYE OF DRAGON-FLY (SECTION).]
"Oh, that is the larva of the dragon-fly. The fly is about to come out
of the case. Just watch it for a while."
[Illustration: LARVA OF GNAT.]
[Illustration: ESCAPE OF GNAT FROM ITS PUPA-CASE.]
The larva of the dragon-fly is one of the ugliest of creatures. It has a
long light-brown body and six legs. It has a fierce wide mouth and
projecting eyes. Attached to its head are two claws, which with a
pincer-like movement, catch up anything eatable and pass it to the
mouth. In its larva and pupa state it has just the same appearance, and
when it is about to change into a perfect dragon-fly it climbs up out of
the water and emerges out of its case, just like the butterfly, and
sails away a perfect and gorgeous insect, leaving its case a transparent
brown shell, still clinging to the reed or grass-stem on which it
contracted its last change.
"Bother the gnats!" said Jimmy brushing some off his face. "There is
nothing interesting about them."
"Oh yes, there is," said Dick. "They lay their eggs on the surface of
the water, making a raft of them, and the larvæ escape through the
bottom of each egg into the water; and I have read that it is a very
pretty sight to watch the perfect insect coming out."
[Illustration: METAMORPHOSES OF PLUMED GNAT.]
"I would prefer their staying down below; they bite me," answered Jimmy.
Crawling along the bottom were numbers of caddis-worms in tube-like
cases made of sticks and stones. Inside these cases are the plump white
grubs which turn into flies.
"Where the bottom is gravelly these caddis-worms make their cases of
little stones," said Frank.
"Yes, and I read the other day that an experiment had been tried by some
one, who took some out of their nests and put them into an aquarium with
some finely-broken glass of different colours, and the caddis-worms made
their cases of this broken coloured glass, and very pretty they looked."
"Their own bodies must supply the glue which fastens the pieces of
gravel or glass together?"
"Yes, it does."
As the fish were biting very badly the boys left the broad early and
went for a stroll. While passing through the village they saw a sale of
stock going on in the open space round which the houses were ranged.
They stopped to look on. The goods which were being sold were the stock
in trade of a chemist, and among them were three large glass bowls, such
as are used for aquaria. These were put up by the auctioneer in one lot,
but there was no bid for them. They were articles not in request in that
rural district.
[Illustration: PUPA-CASE, LARVA, AND FLY OF CADDIS-WORM.]
"Will no one make me a bid? Everything is to be sold without
reservation," cried the auctioneer.
"Five shillings," said Frank.
"Going at five shillings!--going! going!--gone!"--and the lot was
knocked down to Frank.
"What are you going to do with them?" asked Jimmy.
"Make them into aquaria, of course. Don't you see they are just the
thing. The idea came into my head as soon as I saw them."
"Then we can put some water insects in," said Dick.
The glass reservoirs were placed on a shelf in the boat-house, and the
next morning before breakfast they were fitted up. They got a quantity
of fine gravel and sand, and thoroughly washed it in water, so as to
cleanse it from all mud and impurity. This was placed to the depth of a
couple of inches in each vessel, and a rock-work of worn flints was
built upon it. Water was poured in to within a few inches of the top,
and pieces of anacharis were planted in the gravel, their roots kept
down by the stones. In a day or two the water had got clear, and the
plants had taken root, and the boys proceeded to stock the aquaria. The
small brook near afforded minnows and sticklebacks in plenty. In a
stagnant pool they got some newts and water-insects. From the broad they
obtained a few small perch, roach, and bream, and an eel about six
inches long. They at first put these all together without any attempt at
sorting them, and then the following consequences ensued. The
water-boatmen fastened on the heads of the small fish and speedily
killed them, and ate them up. The sticklebacks made themselves at home
at once, and proved very pugnacious, fighting each other, dashing at a
stick or finger, if put into the water, but, worst of all, annoying the
minnows. Each male stickleback took up a position of his own, and
resented any approach to within a few inches of it. With his glaring
green eyes, and scarlet breast, he would wage war against any intruder;
and when an unsuspecting minnow came within his ken he would sidle up to
it, till within striking distance, then dash at it, and strike it with
his snout in the stomach. The perch swallowed the minnows, and when they
had vanished, attempted to swallow the sticklebacks, but the spines of
the latter stuck in the perches' gullets and choked them. The eel, too,
would writhe and poke through the gravel and stir it up, displacing the
weeds and doing a lot of mischief.
[Illustration: MINNOW.]
This led to a general reconstruction of the aquaria. The perch were
taken out and restored to the broad, together with the eel. The roach,
bream, and minnows, were put into two of the aquaria by themselves, and
the sticklebacks and water-insects into the other. Many a fight took
place among the sticklebacks and the water-boatmen, in which sometimes
the one and sometimes the other came off victorious.
[Illustration: SMOOTH NEWT.]
The boys then got some caddis-worms, pulled them from their cases, and
put them into a glass vessel filled with water, and having at the bottom
some glass of different colours broken into small pieces. In a short
time the caddis-worms had made themselves new, parti-coloured cases of
glass, which were quite transparent, and through which the white bodies
of the grubs could be plainly seen. Frank put these in among the minnows
one day, and it was amusing to see the fish darting at the caddis-worms,
thinking they would be soft, succulent morsels, and to watch their
evident astonishment at being foiled by the hard cases. This suggested
an idea to Frank which he afterwards carried out.
None of the sticklebacks kept by the boys built nests or bred, so that
they missed seeing a very pretty and interesting sight. "Fishes building
nests!" I hear some of my readers exclaiming. Yes, sticklebacks do build
nests, and in the number for January 1866 of _Science Gossip_ is an
interesting account of this habit, which I take the liberty of quoting.
When I have observed any fact in natural history myself, I describe it
in my own words; but when I take it from the observation of others, it
is fairer to them to use their own words, and far better in the
interests of truth:--
"Two pair of sticklebacks were procured about the middle of April,--the
males having already put on their spring dress of scarlet and green, and
the females being full of spawn.
[Illustration: METAMORPHOSES OF NEWT.]
"After a few days a small hole was observed in the sand near a large
stone. To this hole one of the males was paying the most assiduous and
extraordinary attention. He was poising himself at an angle of
forty-five degrees or thereabouts; he commenced a tremendous motion of
his whole body, making the sand a pivot, and at the same time beating
the water with his fins. This motion increased regularly in rapidity for
a minute or so, when it ceased abruptly, and the fish darted off, either
in pursuit of some trespasser whom he chastised (the females not even
being exempt), or to obtain materials to increase his nest. These
consisted of pieces of stick or moss, which being saturated with water,
were of such gravity as to prevent their rising. He deposited these with
great care, leaving a perfectly round hole in the middle, and then
having procured a mouthful of sand, laid it over the looser materials to
cement them together.
"When completed, the nest resembled a flattened haycock.
"For about a week after this completion it seemed deserted. But one
morning it was found that some eggs had been laid. These for the size of
the fish are very large, being about the size of a middling-sized shot.
They hatched in about from ten days to a fortnight,--the young fish
remaining in the nest until the yolk-bag was absorbed, when, being large
enough to look after themselves, they went their way. The parent who had
so tenderly guarded them took no further heed of them, and himself
died--such being the case in both instances which came under notice,
both parents sickening and dying from the effects of spawning and
watching, or perhaps from the aquarium not being fitted for their
recovery."
[Illustration: WATER-FLEAS.]
[Illustration: ANIMALCULÆ IN DROP OF WATER, AS SEEN UNDER THE
MICROSCOPE.]
Those who keep aquaria in an intelligent manner and study the habits of
the creatures they imprison, will find it both interesting work, and a
never-failing source of amusement. It is very little trouble. When the
water is put in, and the plants begin to grow, the water need not be
changed. The oxygen produced by the plants will keep the water pure,
and will supply it with air.
[Illustration: FRESH-WATER AQUARIUM.]
The green confervoid growth which rapidly forms on the sides of the
aquarium must not be all wiped off, for it assists greatly in keeping
the water pure and healthy. Tie a piece of sponge to a stick, and with
this you can wipe it off from that side where it obstructs the view,
without disturbing the rest of the aquarium. If you have no cover, and
dust accumulates on the surface of the water, it may easily be removed
by means of a piece of paper laid on the surface of the water for a few
minutes. The dust will adhere to this, and be taken away with it when
it is removed. The confervoid growth is best kept down by the common
water-snail, several of which should be kept in the aquarium.
You must of course feed the fish occasionally with worms, insects, and
bread; but give them very little at a time, or you will foul the water
and render it muddy, and the fish will sicken and die. Keep these few
hints in mind, and you will have no trouble in managing your aquarium.
[Illustration: METAMORPHOSES OF FROG.]
From aquaria to flowers is a sudden transition, but a bunch of violets
has just been held to my nose to smell, and their sweet fragrance has
borne me in thought from my study, where I am burning the midnight oil,
to the green woods and fields of my boyhood, and then a sudden review of
events which have happened since in my life, makes me more thankful than
ever that that boyhood was, as far as natural history is concerned, a
prototype to the boys of whom I am now writing, and makes me wish to
urge the more strongly upon you the almost boundless advantages which
follow the study to all. You will of course clearly see that my aim in
writing this book is not merely to amuse, but to teach you some of the
wonders which lie ready for you to explore, and the delight of seeking
and discovering those wonders. I do not, however, want to moralize,
because if I do you will skip my moralising, so I will pull up in time
and get on with my story.
[Illustration: SEA-WATER AQUARIUM.]