CHAPTER XVI. 



ARACHNID A — 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 A rachnida 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 AracJinida 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 &^g 

 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 o.^^. Nothing 

 like the slow growth of the jfuhis 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 



