COCOONING AND HATCHING OF AN AKANEAD. Q 



Therefore we have to enumerate: the cocoon, snare, nest, para- 

 chute (a somewhat more definite term to replace McCook's "gos- 

 samer "), sperm-web, e/isivat/iincnt and moult-ivcb. Of these 

 constructions the cocoon occurs in all species, and probably the 

 nest also ; these may then be said to be the most conservative 

 or most persistent kinds of architecture in spiders. It is probable 

 that the nest or protective habitation was the first construction 

 to be elaborated, perhaps first merely some cranny that later 

 became lined with silk by the spider ; and that the spider laid its 

 eggs first without lining against the wall of this nest, then later 

 spun upon them a cover of silk. This is of course merely an 

 inference because we know nothing of the ancestors of the modern 

 spiders. But the cocoon, by which is meant the immediate silken 

 envelope of the eggs, may in this way be explained as a deriva- 

 tion of the nest of which it formed at first an integral part ; the 

 original base of the cocoon would have been the silken investure 

 of the nest, the cover of the cocoon a later addition. If this 

 suggestion be correct, then the phylogeny of the cocooning 

 would have been as follows: (i) oviposition against the wall of 

 the nest ; (2) the addition of a cover to the eggs ; (3) a special 

 base spun upon the wall of the nest, the eggs upon which re- 

 ceived a cover (a condition realized by certain attids, clubionids 

 and drassids) ; (4) the formation of a cocoon with base and cover 

 apart from the nest. 



Wagner has distinguished two kinds of cocoons : those made 

 of two pieces, and those of a single piece, a distinction based 

 upon the appearance of the completed structure. I would main- 

 tain, on the contrary, that it is probable that in all modern ara- 

 neads the cocoon is spun of two pieces, first a base, then a cover, 

 foj- I have observed (/. c.} this process in lycosids, agalenids, 

 dictynids, theridiids, epeirids and drassids. One may not judge 

 from the form of the finished cocoon as to its mode of construc- 

 tion, and, so far as I know, in all cases where the process has 

 been followed a base is first spun, the eggs oviposited upon it, 

 then a cover made. There seems to be no positive evidence that 

 the cocoon is ever made in a single piece. One of the best diag- 

 nostic characters of Araneads is the making by the mother of a 

 silken covering, composed of two pieces, for the protective invest- 

 ment of the eggs. 



