82 AMERICAN SPIDERS 



use of his front legs during the visual courtship but wigwags with 

 his palpi, often standing high on the tips of his tarsi. Within the 

 same group such striking differences in courtship are often found. 

 Lycosa gulosa is a comon grassland spider varying in color from 

 gray to nearly black, and exhibiting only slight differences between 

 the sexes. From its courtship antics it once was given the common 

 name of "purring spider." B. J. Kaston explains: 



Immediately upon coming in contact with the female, or 

 within three minutes thereof, the male begins to drum his palps 

 rapidly against the floor of the cage. These drumming move- 

 ments are made so rapidly that a distinct purring or humming 

 sound can be heard. The palps are used alternately and are 

 raised only a very short distance during the process. The body 

 is held at an angle so that the posteriar end of the abdomen 

 almost touches the floor. As a consequence when the male be- 

 gins to twitch his abdomen in a vertical plane, the tip strikes the 

 floor. However, I could not detect any sounds made by this 

 part of the body. It is highly probable that the vibrations set 

 up in the substratum by the tapping movements of the palps 

 and abdomen are perceived by the female. This may exert an 

 exciting influence on her in a manner analogous to that which 

 occurs in web-building species, where the male tweaks the 

 threads of the female's snare. 11 



The male of Schizocosa crassipes has a thick covering of black 

 hairs on the tibiae of the front pair of legs, which are conspicuous 

 epigamic brushes. He extends his long first legs out in front and 

 taps the floor with both about four or five times, simultaneously 

 and in rapid succession. Then the forelegs are raised and the body 

 is elevated high upon the posterior legs, while at the same time the 

 palpi are extended downword to touch the floor below the face. 

 In this position, the brushes on the front tibiae are very conspicu- 

 ously displayed. He advances toward the female with a rhythmi- 

 cally repeated waving of legs, jerking of body, and posturing. A 

 closely allied species, Schizocosa bilineata, bedecked with similar 

 ornaments on the front legs, seems on the other hand to make no 



11 B. J. Kaston, "The Senses Involved in the Courtship of Some of the 

 Vagabond Spiders," Entomologica Americana, Vol. XVI (1936) (new series), 

 p. 114. 



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