COURTSHIP AND MATING 79 



the two sexes part, the female ordinarily making no attempt to 

 attack the male. 



Many of the small running spiders spin little silken cells under 

 stones or in tiny nooks on trees. Wulfila saltabunda, one of the 

 smaller anyphaenids, weaves a little curtain beneath the leaf of an 

 herb or bush and stands upright on the silk. The male stands be- 

 neath the sheet and drums on it with his long front legs and palpi, 

 and at intervals pulsates his abdomen up and down. The female 

 often responds by tapping with her front legs and palpi, and vi- 

 brates the sheet immediately above the male. The male will court 

 the female in this position for hours, but mating ordinarily does 

 not occur until evening. He seems able to avoid the female with- 

 out great effort, and to be relatively immune to her attacks. How- 

 ever, she is much more powerful and can kill him with ease if he 

 approaches her too insistently when she is pregnant or otherwise 

 not ready for mating. 



Some of the gnaphosids, notably Drassodes and Zelotes, are said 

 to take possession of an immature female by enclosing her in a 

 silken cell. Just after her final molt and before she has attained 

 her full strength, the male mates with her. This is possible since the 

 male matures earlier than the female and is able to recognize her 

 as a prospective mate even though she is immature. It is the habit 

 of many of these spiders to live in adjacent silken sacs under the 

 same stone or piece of bark. Not uncommonly, a male in the 

 penultimate stage, when he presumably has no instinct for recog- 

 nizing or sequestering a mate, will be found in a sac with an im- 

 mature female. This suggests that the association in many instances 

 may be only a fortuitous one. 



A few of the sedentary spiders with inferior eyesight have given 

 up life on webs and have become vagrant secondarily. The most 

 interesting example is that of Pachygnatha, one of the big-jawed 

 spiders that live in grass and vegetation especially in cattail marshes. 

 The male prowls among the grass roots and finds his mate by touch. 

 He seizes her and, aided by special spines and long teeth on his 

 chelicerae, holds hers firmly until her mating instincts have become 

 aroused or her hostility forces a retreat. 



Among the crab spiders we find few of the preliminary activi- 

 ties identifiable as true courtship. These spiders live on the ground 

 and on plants and are for the most part diurnal in habit. The eyes 

 of some are fairly large, but the spiders seem to make little use of 



