SCHEFFER : COCOONING HABITS OF SPIDERS. 87 



sents more interesting traits in a general way or shows more 

 tenderness and solicitude in the care of its young than the Ara- 

 neida. If it were the purpose of this article to defend the spi- 

 der's reputation, much could be said that would tend to enhance 

 our respect for them, but the limitations of the subject will per- 

 mit discussion of their conduct along one line only. 



Spiders interest themselves in various spinning operations ; 

 they make snares to trap their prey, silk-lined habitations to 

 shield them from rough weather, drag-lines to serve as bridges 

 and ladders, balloons to bear them aloft in their autumnal 

 flights, fetters to bind the larger insects they capture, and silken 

 sacks in which to enclose their eggs. The use of silk for this latter 

 purpose seems to be almost universal, although many species 

 omit one or more of the other industries from their line of prac- 

 tice. Many spiders use their silk for cocoon fabrication only. 



The majority of spiders live but one year, and in their period 

 of maturity each female makes but one cocoon to enclose her 

 contribution to the perpetuation of the species. There are,, 

 however, many exceptions to this general rule. Some spiders 

 are known to live several years, probably rearing a brood each 

 season, and a number of quite common species, as the Labyrinth 

 spider and the cobweb weaver of our house and outbuildings, 

 lay their eggs at intervals during the summer, adding a cocooa 

 each time to the collection or string. 



In texture the egg-sacks vary from a simple mass of loose 

 floss, through which the eggs can plainly be seen, to a structure 

 whose walls are like parchment, close-woven, and stiff enough 

 to protect the contents from rain and frost through the long, 

 dreary months of a New England winter. The former class is 

 represented by the cocoons of some of our common orb-weavers, 

 such as those that stretch their webs between the timbers of 

 bridges ; the latter class is typified by the egg-sack of the Golden 

 garden spider, a familiar object in the late autumn. 



The modifications of structure to adapt the cocoon to season 

 or environmental conditions are very obvious. Cocoons which 

 are made for summer use only, or are sheltered in some way or 

 protected by extraneous material, are less compactly woven than 

 those meant for wintering eggs or young or those which occupy 

 exposed situations. Again, the composition of the cocoon will 

 depend to some extent on the care the mother spider is to give 



