168 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



case is quite hard. In others, it is left in the flossy condition in which 

 it is originally spun. 



2. While the general method of spinning out the material, as above 

 described, is that which prevails among all Tribes, the composition of the 



cocoon, or general plan of architecture, may be properly sep- 

 Composi- ara j. e( j j n t o th ree distinct modes. In the first the eggs are made 

 tion of i i i 



Cocoons the cer >tre of operations, being first laid upon a circular patch, 



covered by a mass of continuous floss, and thereafter usually 

 enclosed within a seamless case of thickened spinningwork. The protec- 

 tion to the eggs is thus a single and unbroken covering. This method 

 prevails among Orbweavers and Lineweavers. 



In the second method the cocoon covering is spun in two parts. There 

 is first woven a sheet to receive the eggs, and after the eggs have been 

 overspun and swathed a second and similar sheet is made as an outer 

 covering. This method is the prevalent one among Tubeweavers, Salti- 

 grades, and Laterigrades. 



Cocoons classified under the second mode may be subdivided into two 

 well defined groups, viz., first, those in which the covering consists of pure 

 silk ; and, second, those in which the silken covering is strengthened or 

 padded by bits of gnawed bark, sawdust, and various light chippage, 

 daubs or pellets of mud, and sometimes by an entire coating of clay. 

 This mode of providing an armor of extraneous material is most preva- 

 lent with Tubeweavers, although it occasionally appears among Orbweav- 

 ers. Sometimes the armor or upholstery is itself covered over with an 

 exterior silken case, as with Agalena na^via ; but again it forms the outer 

 casing or plaster, as with Micaria limicunse and Clubiona tranquilla. 



The third special mode is that which prevails, one may say almost 

 universally, among the Citigrades, and which is probably practiced by the 

 Tunnelweavers also. It consists in spinning a single sheet, within which 

 the eggs are deposited, which is subsequently pulled over the egg mass, 

 and pinched by the jaws into a globular covering, the selvage of which is 

 united with sufficient firmness to adhere until the spiders are ready to 

 leave the cocoon, when the seam yields sufficiently to allow the escape of 

 the inmates. 



3. A third point of comparison is as to the disposition of the cocoon 

 by suspension or attachment. We may divide the cocoons of all tribes 



broadly into two classes, (I.) hanging cocoons and (II.) fixed 

 cocoons. The hanging cocoons may be subdivided into those 

 (1) which are suspended within the snare and (2) those which are 

 suspended or attached outside of or near the snare. The latter class may 

 again be divided into (a) those which are suspended with external pro- 

 tection and (b) those which are suspended without external protection. 



Of spiders that hang their cocoons within the snare, the Orbweavers 

 have a number of representatives, as especially Epeira labyrinthea, Cyclosa 



