176 SPIDERS 



mistaken identity, one male being stimulated sexually by another 

 of the same species, but Crane (1948) regards them as threat dis- 

 plays and she has shown that in Corythalia spp. such behaviour is 

 distinct from courtship. The fringed, iridescent legs are always 

 used in threat displays, but are never employed in courtship. 



Among web-builders courtship usually consists of the male 

 telegraphing to the female occupant of a web by tweaking the 

 threads as he approaches, but in later stages a tactile stroking of the 

 body precedes coition. This routine may constitute a tactile dis- 

 play almost equal in interest to the visual displays of the long- 

 sighted hunting spiders. 



In ethological terminology, the function of courtship is to pro- 

 vide releaser stimuli for the mating instinct which at the same time 

 block hunger drives. The concept of recognition may not in fact be 

 necessary. 



Polygamy is the custom among spiders and it is indeed wise for 

 the male to retreat hastily immediately copulation is finished. It is 

 probable that the male Atypus affinis is not given any opportunity 

 to escape from the female's lair, but there is no evidence that the 

 widow will refuse admittance to a succession of husbands. In con- 

 trast it seems probable that Amaurobius ferox females mate only 

 once. Occasionally the sexes appear to live together peacefully, but 

 experiment has shown that in the case of Meta segmentata this 

 apparent faithfulness is fictional and males may visit the web of 

 more than one female. In this species the males often kill one 

 another. Since courtship is deferred until the female is engaged in 

 trussing a victim or eating a meal, it is not uncommon to see it 

 taking place over the dead body of a vanquished rival (Bristowe, 

 1941).* 



Life history 



Spiders lay their eggs in retreats and cocoons which they con- 

 struct of silk and often mount guard over them until the young 

 have hatched. Theraphosidae prepare great flabby egg purses in 

 their burrows and guard them assiduously, while the delicate 

 silken sacs of the trap-door spiders often hang from the side of the 

 tube. Wolf spiders (Lycosidae) carry their globular cocoons 

 attached to their spinnerets wherever they go, and after hatching 



