248 
Peckham—The Sense of Sight in Spiders. 
and at six inches he made his display, raising himself high upon 
his six back legs, while he lifted the first pair obliquely forward 
and upward, crossing the tips and widely extending his palpi, 
while his abdomen was dropped so that it dragged on the ground. 
He advanced with a swaying motion. When he was close to 
her she ran rapidly away, leaving him in her corner, and taking 
up her position fifteen inches away remained quiet for some time 
with her eyes fixed upon him. Later on he noticed her when 
she was quiet, eleven inches away, and she followed him with 
her eyes, moving her head, as he walked all around the box, at 
a distance of from ten to fifteen inches. 
A female of Marptusa familiaris standing four and one-half 
inches lower than the male and thirteen inches away followed 
him with her eyes as he moved slowly back and forth in a semi¬ 
circle before her. They showed, she by a characteristic vibra¬ 
tion of the palpi, he by the outstretched position of his first 
legs that each distinguished the other's sex. We have never 
seen the male of any species make his display before the female 
at a greater distance than this. The same performance was re¬ 
peated when they were nine inches apart. 
it is evident that the spiders recognize each other by sight 
and not by any other sense, as they remain perfectly uncon¬ 
scious of each other’s presence when back to back no matter how 
excitable they are when they come within each other’s range of 
vision. The males of Dendryphants capitatus are extremely 
quarrelsome, especially in the presence of the female, yet some¬ 
times two males while displaying before the females, will each 
remain unconscious of the close proximity of the other, even 
Dacking up and bumping into each other. We once interrupted 
the courtship of a male of Dendryphantes elegans by taking him 
out and gently blinding his eyes with paraffine. He was then 
restored to the box where he remained quite indifferent to the 
presence of the females, which had excited him so much a few 
moments before. 
The same experiment was tried upon a male of Saitis pulex. 
While dancing in the greatest excitement before a female he 
was taken from the box and his eyes were blinded with paraffine. 
He was handled gently, and the paraffine was not hot. He was 
