THE PVR A LID IN A. 
I 39 
The Bordered Pearls, the Mother of Pearls, the long-winged 
Pearls, and the small Magpie are well-known moths which belong 
to the genus Botys. They have long trunks and very pretty wings. 
The caterpillars are rather long and are extremely rapid in their 
movements. They twist up the leaves with a few silken threads 
and make safe hiding places, the small Magpie choosing the sting- 
ing nettle for its particular habitation. Its membranous legs are 
particularly adapted for walking on plain surfaces, but not for 
climbing. Everybody may recognise them, because when they are 
disturbed they wriggle about in the most extraordinary manner. 
Of all the Lepidoptera the Hydrocampidce are perhaps the 
most extraordinary so far as their methods of life are concerned. 
The moths fly and enjoy the air as much as any others, and 
cannot be distinguished from those whose caterpillars live on 
dry land. Their breathing apparatus is like that of other 
moths, and they have the habits of the other night-flyers. But 
the caterpillars live in the water and respire in two manners. 
In some kinds of the Hydrocampidce the caterpillars live in the 
water, surrounded by a great bubble of air, and others positively 
have gills or branchiae, and are surrounded and bathed by water. 
This is a most extraordinary fact, for the moths which are pro- 
duced by metamorphosis from these caterpillars, resemble each 
other to a great extent, and it shows how slight the distinction 
may be between aquatic and air-breathing animals, and how nearly 
the origin of the separate conditions may be allied. The gills 
are in the shape of filaments, like those of the larvae of the 
caddis flies, but there is one kind ( Paraponyx ) whose larvae have 
large branchiae and also spiracles. Its pupa is found in a cocoon 
amongst leaves under water, but it does not appear at present 
certain how the moth gets out of the chrysalis case without 
drowning itself. 
There is a common species in France which lives upon the 
pond weed. Whilst in the caterpillar state it cuts two pieces 
of leaf and fashions them so that they become oval in shape 
and nearly equal in size. It unites them by their margins, sew- 
ing them as it were with a little silk, and leaving an opening 
for its head and the first segments of the body. It drags 
this house about under water, but sometimes leaves it for a 
