Marvels of the Universe 799 
more to come. As far as we know, they all lay eggs ; none bring forth the young alive. Different 
species have different methods of depositing the ova, some in streams or swift-running water deposit 
the eggs on stones, others in ponds on the stems and leaves of water plants ; some bore holes in the 
outer skin of reeds in the water and deposit the eggs underneath. Then one or two species deposit 
their eggs on the mantle of fresh-water mussels, and another of the same genus always deposits 
its eggs in the fresh-water sponge. The time from the deposition of the ova to the appearance of the 
larvee varies with different species from a few days to over a month; and when the larve is 
examined, it will be seen they are totally unlike their parents, both in structure and colour. Unless 
we had bred the larve at home, like the late Saville Kent succeeded in doing in so many cases, we 
should be quite unable to recognize them, or give them their proper name. In this stage, unlike the 
adult, they only have six legs. Some species are quite transparent, but all the larvae have very 
delicate colouring. It is during this stage they become parasitic, attaching themselves to all kinds 
of hosts; different species of larvee selecting their own particular favourite. Certain species are 
found in great numbers on water scorpions and water beetles. The Large Water-Beetle is hardly 
ever found without one or more of these parasites attached to its under-side. | When once the larvee 
have firmly attached themselves with their mouth organs to their particular host, the six legs they 
started existence with are of no further use to them, so they usually fallaway. The larve gradually 
get larger and larger, until in the following spring they are ready to burst the envelope in which 
they are confined and come away again as independent free-swimming creatures. The empty 
envelope and mouth organs of the Mite remain on the host for some little time after the lodger 
has left. The Mite has now entered on its intermediate stage known as the nymph. It has now 
much the appearance of the 
adults and it has eight legs. 
Its colouring is still weak, and 
we cannot judge to what sex 
it belongs, but we can make a 
good guess at the species, and, 
if not the species, we are able 
to place it in its right genus. 
It grows a great deal in this 
stage and it is always free, 
never parasitic. When about 
to turn to the adult it usually 
gets into some  out-of-the- 
way place on a water plant, 
the fork where the leaves 
erow from the stem being a 
favourite place; it attaches 
itself firmly and remains for a 
few days in an inert state; its 
legs very often again falling 
away as useless. At the proper 
time the skin splits and the 
Mite again takes to swim- 
ming, this time as an adult § ie 
Mite. At first it is not fully [By B. 7. Draper. 
developed, the skin being soft ONES OE SUHE SW ASTER MURES: 
ail ne (bwtky caall Ha joioypare. — g, ep Cieante Mr ents Cin reign eee EAPO 
tion to the legs and other “feelers.” 
