xii] STRIDULATION 109 



to produce a sound, though sometimes the "keys' 3 

 are on the mandibles and the spines on the palp. 



In Staten Island there is a wolf-spider Lycosa 

 kochi which is known as the "purring" or "drum- 

 ming" spider because of a curious habit which the male 

 has, at mating time, of rapidly drumming on the dead 

 leaves in a wood with its palps. It runs hither and 

 thither over the ground as if in search of something, 

 pausing at short intervals to " purr," and the sound 

 had frequently been heard and correctly attributed 

 to the spider before the way in which it is produced 

 was discovered. In this case it is probable that the 

 production of sound is not the object of the spider at 

 all, for we have no evidence that wolf-spiders hear. 

 On the other hand rapid tapping with the palps is 

 a very characteristic action with male spiders at 

 mating time, and it is easy to believe that contiguous 

 dry leaves would conduct vibrations to a female at 

 some distance away and inform her of the presence 

 of the male. Just so, as we have seen, our English 

 Theraphosid announces his arrival by tapping on the 

 exposed part of the nest of the female. 



