CHA PTH 1s, 
HORIZONTAL SNARES AND DOMED ORBS. 
i 
Tue Orbwebs heretofore considered all belong to the general division 
described as vertical orbwebs. The snares to be considered in this chapter 
are known as horizontal orbs. The horizontal orbweb in all es- 
oo earings sential particulars is woven like the vertical orb and differs chiefly 
berosa, i the fact that it is usually hung wholly or partly in a 
horizontal position. 
In the species making vertical webs, the habit is so firmly fixed that 
the spiders rarely deviate therefrom, and never, except under circumstances 
which constrain a departure. Nevertheless, it is interesting to remark that 
sometimes they do spin orbs that more or less approximate the horizontal. 
Occasionally these orbs are entirely horizontal. For example, I have 
known a brood of young Epeira sclopetaria, freshly escaped from the co- 
coon, to-spin upon the same object minute orbs, some of which were vyer- 
tical, while others were as truly horizontal as though they had been made 
by a species that habitually weaves an orb of that sort. Fig. 141. It was 
not difficult for me to determine that these individuals were influenced to 
an abnormal act by the conditions under which they wrought. It was 
comparatively easy for them to get foundation lines so placed that a hori- 
zontal web almost inevitably resulted; while, on the other hand, 
Varia- the frames for a vertical web could not haye been obtained 
om a except with the greatest difficulty. Yet, in the case of a few of 
Plane. ‘the same brood nearly as great difficulties were overcome, and a 
vertical web was made. For example, the little fellows in the 
cut (Fig. 141) found it easy to weave an orb horizontally around the metal 
frame that supports the lamp chimney, and this they did. _But others fol- 
lowed the specific habit and sent down lines to the table, making a 
triangular frame and a yertical orb within it. 
So, too, it may be said that spiders which make horizontal snares are 
sometimes constrained by difficulties of the site chosen to deyiate more or 
less from the horizontal plane. Indeed, I have seen the orb of Tetrag- 
natha inclined at almost every angle, and occasionally haye found it spun 
in an absolutely vertical position. 
. (150) 
