MATERNAL INSTINCTS: MOTHERHOOD. 185 



III. 



When the eggs are laid the spider mother proceeds to spin the outer 



envelope by which they are protected, and within which the progeny, when 



hatched, may find a comfortable home until sufficiently matured 



b ape o ^ Q k e gi n }jf e f or themselves. This external structure differs, 

 Cocoon. 



among various species, in shape, size, interior arrangement, and 



more or less in the character of construction. The details of these points 

 have appeared in the preceding chapters, and they form some of the most 

 interesting features in the life habits of araneads. The cocoon may be 

 described in general terms as consisting of a silken sheet or sac surround- 

 ing the eggs, a padding of greater or less compactness above that, and a 

 case of a more or less compact texture surrounding the whole. 



The shape of the cocoon appears to have no special relation to the 

 maternal instinct, but is probably regulated by the habits of the particular 

 species and the character of the cocoon site chosen. It has already been 

 seen that the forms, although at first view they seem to be quite varied, 

 may, by analysis, be reduced to the round or hemispherical. In other 

 words, the eggs, as they drop from the spider's ovaries, naturally assume 

 a more or less rounded form when the cocoon swings free; and when ex- 

 truded against a fixed surface as naturally form into a hemispherical mass. 



This is simply the result of the law of equilibrium. As the maternal 

 care is directed solely to covering up and protecting the eggs, the shape 

 of the egg mass inevitably regulates the shape of the spinningwork woven 

 around it. It thus would seem that the maternal purpose is shown in the 

 fact of enclosing the eggs within the cocoon, and not in the external shape 

 w r hich that cocoon assumes. 



However, a measure of maternal interest and intelligence is undoubt- 

 edly found in the architectural details of the cocoon. I have show T n (Chap- 

 ters IV. and V.) that these have a tolerably wide range; that 

 a erni- gome cocoons are extremely simple in their structure, and others 

 Structure c l u ^ e complex. To what degree are these differences regulated 

 by maternal affection and intelligence? This question cannot be 

 considered wholly from the standpoint of the cocoon structure itself, for 

 other elements enter into consideration, as the natural environment chosen 

 for a cocoon site, or the artificial environment prepared for it. That is to 

 say, a cocoon may be quite simple in its structure, having little spinning- 

 work to directly enclose the egg mass, but, as in the case of Dolomedes, 

 have a supplementary protection of a leafy tent, and an associated en- 

 closure of intersecting lines, which add materially to the protection of 

 the eggs. Of course, in thinking upon the degree of intelligence and 

 affection exhibited by such a mother, the external protection must be an 

 important factor. 



What is the relation between the simplicity or complexity of a cocoon's 



