and the three spined sticklebacks are, without doubt, the most
wonderful fish for their size that are common to our waters. They will
live well in either fresh or salt water aquaria, building nests and
raising their young under all discouragements. The male builds the nest
for the female to lay her eggs in. The nest is composed of plants
cemented together with a glue provided by the male, who also carries
sand and small stones to the nest in his mouth, with which he anchors
it. During the breeding season the male assumes the most brilliant hues
of blue, orange, and green; previous to this season he is of a dull
silvery color. When an enemy approaches the nest, be he large or small,
he will attack him, inflicting wounds with his sharp spines. Nor will he
allow the mother of the young sticklebacks to come near, as she is so
fond of her babies that she often forgets herself and eats them up. When
the young "tittlebacks," as they are often called, swim too far from the
nest, the male takes them in his mouth and brings them back, throwing
them out with such force that they make many somersaults before landing.
Sticklebacks are the smallest known fish when first hatched out of the
egg, being nearly invisible.

[Illustration: DRAGON-FLY.]

Here is the dragon-fly, as he looks before he gets his wings. He lives
on the bottoms of ponds when he is young; but at a certain age he
ascends to the surface, and crawling out of his old clothes, comes forth
an unmistakable darning-needle. When he lived under the water he had
very large and long jaws, folded up on the under side of his head. If a
fish came within reach, he would dart out this curious trunk, and
seizing it, convey it to his mouth. He also has the power of taking in
and squirting out water from his tail; this action forms a current,
which draws small insects within his reach. The taking in of the water
is also his method of breathing, and the ejecting of it with force
propels him through the water.

[Illustration: BOAT-FLIES.]

Water-boatmen, or boat-flies, are so named from their resemblance to
tiny boats with oars. As they have to swim on their backs, they are
provided with large and very observing eyes. When they breathe they come
to the surface, and by a quick diving motion, and the assistance of
numerous stout hairs on the hind parts of their bodies, they entangle a
mass of air, which, as they descend, spreads, giving their bodies a
bright silvery color.

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