88 AMERICAN SPIDERS 



at the lowest point of the circle, he suddenly snaps the tarsus 

 and metatarsus upward, stiffening and raising the leg and thus 

 exposing more completely its under-surface. While this is going 

 on with the first pair, he is continually jerking the third pair up 

 higher over his back, as though unable to get them into a satis- 

 factory position, and the abdomen is kept twitching. 16 



Such a display can be carried even farther to include virtually 

 all the legs. Euophrys monadnock is a boreal spider that lives in the 

 moss and lichens of open pine forests, frequently being found in 

 the western mountains. The handsome little male (Text Fig. 2, F) 

 displays the orange femora of his hind legs when he postures before 

 the female. 



The palpi, jet-black with yellow ends, hung down in front; the 

 first legs, black with pale tips, and fringed with long, thick, pur- 

 plish scales, were thrown diagonally upward; the body was 

 raised high on the tarsi of the second and third pairs, the third 

 being lifted so that the colored femora would be seen over the 

 second, while the legs of the fourth pair were dropped and held 

 at just the angle that brought the femora into view between 

 those of the second and those of the third pair. In this difficult 

 attitude, the spider began to move. There was none of the awk- 

 wardness shown by Pellenes (Habronattus) in trying to keep the 

 third leg in position; indeed, there was no muscular action vis- 

 ible as he glided smoothly back and forth, while the female, 

 turning from side to side, kept him constantly in sight. 17 



The Web Builders. The spiders in this category are for the most 

 part species that have poor eyesight. Many are confirmed sedentary 

 types or put a considerable reliance on silk, thus effectively obvi- 

 ating a real need for keen vision. In fact, they have extended their 

 snares in ways that carry far beyond the limits of ordinary sight. 

 Through the medium of her web threads, the male is able to per- 

 ceive with reasonable certainty the presence of a female of his spe- 

 cies, and to diagnose her attitude. Courtship among the web spin- 

 ners usually consists of finding out how the land lies, then tele- 



16 G. W. and E. G. Peckham, "Additional Observations on Sexual Selection 

 of the Family Attidae," Occasional Papers Nat. Hist. Soc. } Wisconsin, Vol. i 

 (3) (1890), p. 119. 



17 G. W. and E. G. Peckham, "Revision of the Attidae of North America," 

 Trans. Wisconsin Acad. Sci., Vol. XVI (1909), p. 360. 



