NATURAL HISTORY. 5 
If a few of these eggs are deposited in a vessel 
of water, and exposed to the sun, in favourable 
weather, they will be hatched in a few days. 
When the young first make their appearance, 
the head is larger and the tail longer in propor- 
tion to the size of the body than when full 
grown; they are now remarkably active; at 
this period, if about half a dozen be put into 
an aquatic live-box, with a sprig of moss, as 
directed in the “Microscopic Cabinet,” they will 
afford an interesting spectacle under the micro- 
scope. When a few days old they shed their 
skin, and after the operation, which occupies 
some time, they are almost colourless, especially 
about the head; their activity forsakes them, 
and they abstain from food. As they recover, 
they gradually assume their variegated tints. 
If they are now supplied with one or two small 
blood-worms (larve of the Chironomus plumo- 
sus),and placed under the microscope, an alter- 
nating motion of the glottis will be perceived, 
and, as the digestion of the coloured fluids of 
the worm proceeds, the alimentary canal, the 
different vessels, and their ramifications, will 
acquire distinct colours, forming a strong con- 
trast with the transparent integuments  sur- 
rounding them. 
