THE HUNTING SPIDERS 211 



are seen to intergrade with the Agelenidae in their habits as well as 

 in structure. 



The pisaurids are often cited, and with considerable justification, 

 as providing the outstanding example of maternal devotion among 

 all spiders. Many spiders guard their eggs for varying lengths of 

 time, but few have made of it a complicated ritual that gives pro- 

 tection to the young until they are ready to scatter. Only the wolf 

 spiders exercise equal care, and they are close allies of the pisaurids. 



The first act of the pisaurid mother in behalf of the coming 

 generation is the spinning of a silken cover around her eggs. The 

 sac is a great ball, usually housing several hundred eggs, which is 

 at first white but usually becomes gray or even brownish. From 

 the time it is made until the spiderlings are ready to emerge, the 

 mother carries this treasure around with her wherever she may go, 

 holding it between her long legs and underneath her body (Plate 

 XXII). The claw tips of her chelicerae are inserted in the ball, her 

 pedipalps press around the sides in front, and silken lines from her 

 spinnerets moor it securely from behind. It is often so large that 

 the mother is forced to run on the tips of her tarsi in order to hold 

 it clear of the ground. The difficulty of transporting such a tre- 

 mendous object seems to be very great, and it is fortunate that this 

 habit is operative at a time when the normal desire for food is con- 

 siderably inhibited. A few of the fisher spiders transfer the egg 

 sac to their spinnerets and drag it about as do the wolf spiders, but 

 most of them have retained the ancient and awkward method. 



Dolomedes carries the ball until just before the young are ready 

 to emerge, or until a short time after emergence, then fastens it to 

 a suitable spot at the end of a branch of some herbaceous shrub. A 

 three-lobed leaf is often chosen as the site, and the leaflets are pulled 

 down and tied with silk to form a cosy retreat, the nursery web. 

 It may be supposed that the female aids the young to escape by 

 opening the egg sac; thereafter the babies quickly spin their tiny 

 lines and scatter within the confines of the nursery. The mother 

 remains outside the retreat guarding the spiderlings until they have 

 molted and moved away, a period often of more than a week. 



Pisaurina mira usually prepares her nursery well in advance even 

 of the egg laying. She displays a decided preference for the poison 

 ivy, using its leaflets for the top and sides of her retreat and spinning 

 up the opening below with a platform of silk. After the eggs are 

 laid and enclosed in a sac, Pisaurina hangs on the outside of the 



