440 TRANSFORMATIONS OF INSECTS. 
minutes. It would appear, then, that the aérated fluid is not 
taken into the trachee. 
The mouth of this spider is a very important organ, and has 
to do with much besides sucking and piercing. It is formed like 
a beak, large, and elongated into the shape of a gutter; and 
it encloses part of the two piercing blades or mandibles, which 
can unite to form a second sucker-shaped projection. The palpi 
are hooked at the end, and enable the insect to hold on to the 
potamogetons and other water-weeds, whence it derives part of 
its nourishment by the aid of. its piercing suckers. It eats other 
matters, however, for the spider may be seen feasting upon the 
flocculi, which contain myriads of animalcules and microscopic 
plants, and which float in the water. 
Eight legs exist, and the three hinder pairs are the longest and 
are suited for swimming, whilst the others are shorter. All are 
furnished with two long hooked claws, which are retractile. 
M. Duges saw the females making pin-like holes in the soft 
central tissues of the potamogetons with their beaks, and then 
placing their eggs within, so that an opaque appearance was given 
to the plants. The eggs are deposited in great numbers,,and 
hundreds of these oblong and reddish-brown ova are laid by each 
female. The employment of the mouth-pieces as instruments for 
ovipositing is very interesting. The female dies soon after laying, 
and her body becomes flaccid first of all. She does not cover up 
the punctures in the plant with any secretion, but leaves the eggs 
to be protected by the cells of the plant. The larve of insects 
and many worms devour the eggs, but some always remain to 
become hatched. The egg-laying takes place towards the end 
of May, and six weeks elapse before the larve are hatched; and 
during this time the potamogeton leaves and stems die and 
undergo decomposition, so that the newly-born spiders escape 
without difficulty from the surrounding tissues. 
The larve have six legs, which are placed very closely to- 
gether, and each leg is hairy and adapted for swimming, and, 
moreover, it is clawed. The feet are red in colour, and so is the 
body, which is oval, flat beneath, and convex above. In front 
are the two great eyes on each side, and between them, and pro- 
jecting backwards, is a kind of scale. The beak looks exactly 
