240 
PecJcham—The Sense of Sight in Spiders . 
One would naturally expect that the orbweavers would not be 
very far-sighted. Living as they do in webs, the vibration of 
the lines would seem to be sufficient both to enable them to 
capture their prey and to carry on the preliminaries to their 
mating. Still the evidence offered by Rev. Mr. O. P. Cam¬ 
bridge, and by Hentz, to some extent confirmed by our own ex¬ 
periments, renders it fairly probable that some of the seden¬ 
tary species have distinct vision for stationary objects at from 
two to four inches. Cambridge, as quoted by Dr. McCook, 16 
“records that he has more than once seen an English Orb- 
weaver, Meta segmentata, drop from her web upon an insect 
which it had espied on the ground a little way below it, and 
ascend again with its prize by means of the line drawn from its 
spinnerets in the descent. ” As Dr. McCook goes on to say, 
this is certainly a remarkable degree of keen sightedness for an 
Orbweaver, and especially for one that habitually affects a 
shadowed habitation. 
We have confirmed the statement of Hentz, 17 that Eperia 
prompta sometimes catches its prey by running and leaping 
upon it, like an Attus. We have also made some experiments 
upon the Therididse 18 which showed that Theridion blandum and 
Theridion frondeum recognized their cocoons at three and at 
four inches, respectively. In these spiders, although the cocoon 
is not attached to the mother’s body, she keeps guard over it 
and evidently knows it by sight. 
The evidence that we have to offer upon the subject of sight 
in the Attidse is based upon a study of twenty species. This 
study has extended over eight successive summers and we have 
notes of many hundreds of observations. We have experimented 
more with the Attidse than with other families, both because 
the habits of these spiders make them especially available and 
because it was easy for us to carry on a double set of observa¬ 
tions while we were studying their mating habits. 
Unlike all the other families of spiders with which we are 
acquainted, nearly all of the Attidse, when shut into a box which 
u Ibid., p. 287. 
17 Ibid., p 112. 
18 Mental Powers of Spiders, Journal of Morphology, Vol. I, p. 401. 
