3 28 



ARACIINIDA ARANEAE 



CHAP. 



chelicera and the inner surface of the femur of the pedipulp were 

 finely striated at the point, where they were rubbed together when 

 the palps were agitated, but though the appropriate motion was 



frequently given, he could 

 hear no sound. 



Meanwhile the noise 

 produced by a large Thera- 

 phosid spider in Assam 

 ( Chilobrachys stridu lans) 

 had attracted attention, 

 and its stridulating appa- 

 ratus was described in 1875 

 by Wood - Mason. 1 The 

 sound resembled that ob- 

 tained by " drawing the 

 back of a knife along 



the edge of a 



strong 



FIG. 184. ChUobrachys stridulans in stridu- COmb. 



lating attitude. After Wood-Mason. Natural Subseciueiltlv Certain 



Sicariid spiders of a genus 



confined to the southern hemisphere were heard to produce 

 a sound like the buzzing of a bee by the agitation of their 

 palps, and both sexes were found to possess a very perfect 

 stridulating organ, consisting of a row of short teeth on the 

 femur of the pedipalp, and a striated area on the paturon of 

 the chelicera. 



Pocock lias recently discovered that all the large kinds of 

 Theraphosidae in the countries between India and New Zealand 

 are, like Chilobrachys, provided with a stridulating organ. In 

 1 1 11 'si spiders also it is between the palp and the chelicera. and 

 consists of a row of teeth or spines constituting a "pecten," and 

 a scries of vibratile spines or "lyra," but whereas in Chilobrachys 

 and its near relations the lyra is on the palp and the pecten on 

 the paturon, in other spiders the positions are reversed. The 

 lyra is a very remarkable organ, consisting of club-shaped, often 

 leathery bristles or spines, which lie parallel to the surface to 

 which they- are attached, and which is slightly excavated for 

 their reception. 



Lastly, many African Theraphosids possess a similar organ, 



c. Aifitit. .SW. JJcng. 1875. p. 197. 



