242 
Peckham-^-The Sense of Sight in Spiders. 
with a certain leaping gait. The moment, however, it has dis¬ 
covered a fly, all its motions are altered; its cephalothorax, if 
the fly moves, turns to it, with the firm glance of an animal 
which can turn its head; it follows all the motions of its prey 
with the watchfulness of the falcon, hurrying its steps or slacken¬ 
ing its pace, as the case may require. Gradually, as it draws near 
to the unsuspecting victim, its motions become more composed, 
until, when very near, its movements are entirely imperceptible 
to the closest observation, and, indeed, it would appear per¬ 
fectly motionless, were it not for the fact that it gradually 
draws nearer to the insect. When sufficiently near it very sud¬ 
denly takes a leap, very seldom missing its aim. ” 20 
There is a considerable difference in the character of the dif¬ 
ferent species as well as among individuals of the same species, 
but we have found nearly all of our Wisconsin Attidae very good 
subjects for experiment. 
In the summer season it is our habit to keep from twenty to 
forty species in confinement for several weeks at a time. They 
are put into boxes of two sizes, the larger ones being 15 inches 
long by 11J* wide and three deep, and the smaller long by 
5f wide and 2-J- deep. The sides of each box are marked off 
into inches so that the distances of the spiders from each other 
and from the flies can be easily noted. The' bottom is of cot¬ 
ton cloth and the top is a glass slide. 
As may be easily imagined it is something of a task to feed 
so many prisoners. Our principal food supply is found in the 
gnats that settle upon the wire screen which encloses the porch 
of our cottage. These are well liked by all the smaller species, 
while the larger ones take house-flies, May-flies, and small 
grasshoppers. 
When several gnats were put in at one end of a box contain¬ 
ing six or eight spiders their attention was immediately excited 
and two or three of the gnats would be captured almost before 
they had settled on the sides of the box. Those that were not 
caught would settle at once and become motionless. As the 
bodies of these little gnats were white and nearly transparent 
they were very inconspicuous, whether resting upon the sides 
30 Ibid., p. 56 
