CHAPTER XVI. 
ARACHNIDA — -SPIDERS. 
If the question, Do spiders undergo metamorphoses ? were asked 
of the ordinary observers of Nature, probably an answer in the 
negative would almost invariably follow. Whoever saw a spider 
in the form of a grub transform into a pupa, and then spring into 
web-spinning life ? might be a question asked as an answer to the 
demand just made, which savours to a certain extent of absurdity. 
But as a matter of fact, many Arachnida do pass through the stage 
of larva, nymph, and perfect insect, and those of one great order of 
the class are almost invariably transformed. A metamorphosis is 
very decided in some, and a further change even is superadded in 
certain genera. 
The majority of the Arachnida that do not undergo metamor- 
phosis shed their skins from time to time, or moult, and internal 
changes go on before and during these external alterations, which 
are very considerable and important. Moult after moult produces 
fresh changes and the appearance of new structures, so that the 
sum of these alterations may almost equal in amount those which 
occur at stated periods in the spiders which undergo metamor- 
phoses. Nevertheless, the moulting spiders are born from the egg 
much more fully developed than those which suffer metamorphosis. 
These last are hatched when only three pairs of legs are observ- 
able, but the others present the rudiments of four pairs long before 
they are sufficiently developed to crawl from the egg. Nothing 
like the slow growth of the Julus is witnessed amongst the moulting 
spiders, but they are born feeble, and their limbs are not strong, 
and they pass through an infancy, as it were, and moult several 
