Habits of the Spiders. 
241 
is supplied with light and air, seem entirely unconscious of the 
fact that they are prisoners. They catch flies and devour them, 
sun themselves, mate, lay their eggs, and indeed carry on all the 
affairs of their daily life in the most natural and unconcerned 
manner imaginable, passing a whole summer in confinement 
with an appearance, at least, of perfect contentment. 
The movements and attitudes of the spiders of this group are 
wonderfully varied and expressive, and indicate very delicate 
shades of feeling. For example, a female of Pbidippus mor- 
sitans stalks a fly with a stealthy, menacing air, but when she 
is about to pounce upon and devour a male of her own species, 
there is added to this an appearance of something so evil and 
malignant that one almost sympathizes with De G-eer in the 
feelings of horror and indignation with which this sight filled 
him. The males in the mating season, throw themselves into 
one position when they catch sight of a female and into quite 
another at the appearance of another male. Indeed their attitudes 
express so many shades of excitement, tempered more or less by 
caution, and of jealousy of each other as to make a very dramatic 
performance for the observer. 
This power of expression through different attitudes and 
movements is of great assistance in determining not only 
how far the spider can see but how much it recognizes of what 
it sees, or, in other words, its power of distinct vision, since it 
acts in one way when it catches sight of its prey, in another at 
the appearance of a male of its own species, and in still another 
when it sees a female. Dr. McCook says: “Their rapid and 
marked change of manner when prey is sighted, the mode of 
approach, like the action of a cat creeping upon a bird, the 
peculiar behavior displayed when the final spring is made, are 
not to be accounted for on any theory other than a keen sense 
of sight. ” 19 
Similar observations have been made by Hentz on Marptusa 
familiaris. Of this spider he says: “ It dwells in cracks around 
sashes, doors, between clapboards,etc., and may be seen on the 
sunny side of the house, and in the hottest places, wandering 
in search of prey. It moves with agility and ease, but usually 
™ Ibid., v 286. 
16 
