96 Journal of Comparative Neurology. 



Gallery located in one end. Guard sheet absent. 



The above might be taken as a general type of" the irregular 

 web. But the following observations made in the same locality, 

 upon the same species, at the same will illustrate how the spider 

 adjusts its web to slight changes in the environment. 



Example II. — Location : bottom lands bordering on a 

 creek. 



Main sheet large, horizontal, irregular in outline, attached 

 to two logs and to the tops of several weeds. In the midst of 

 this sheet a branching weed was growing. The branches of the 

 weed pierced the web in several places. In all cases the web 

 was intimately connected to these branches. Gallery in one 

 end. Guard web absent. 



In the following case, the spider has certainly become mas- 

 ter of the situation. 



Example III. — Location : stone wall, above a hole and 

 beneath a projecting ledge. 



Main sheet irregular in outline, intimately attached to the 

 wall, extending as a horizontal bridge from stone ledge to stone 

 ledge across a wide hole. Gallery ni the back part of the web, 

 about half way between the two extremes. Guard sheet very 

 high, extendfng along the whole outer edge of the web and 

 attached to a stone which roofs the web. Snares few, extending 

 from inner edge of web to the stone roof. 



This device is a most effectual insect trap. No doubt in 

 sects resting or walking on either ledge often attempt to pass 

 through this trap to the ledge beyond. Once inside of the struc- 

 ture, there is no escape. The insect cannot escape to the right, 

 because the wall is there ; it cannot escape to the left, because 

 the guard sheet is there ; it cannot escape above, because the 

 stone roof is there ; it cannot escape celow, because the main 

 sheet is there. But it must contmue along the broad way that 

 leads to destruction. Sooner or later it impinges against a snare, 

 falls upon the web, and is captured by the expectant spider. 

 Was this web the result of blind instinct? I think not. It 

 must not be supposed that all of these irregular webs are hori- 

 zontal. Usually they are so, but often they are more or less in- 

 clined. The following observation is an illustration. 



