ENGINEERING SKILL OF SPIDERS. 221 
that a wire suspension bridge is swung across a valley or stream without 
engineering skill, as to think such spinningwork structures are wholly 
without handicraftmanship of some sort. 
The Speckled Tubeweaver (Agalena neevia), which is probably the 
most abundant familiar spider of our fauna, affords admirable illustra- 
tions of this facility. In a stable at Almora, Wallingford, the 
following form of a sheeted web of this species was observed. 
The upper sash of the stable window had been lowered for pur- 
poses of ventilation, thus probably rending the original snare. But in one 
of the upper corners of the window frame and within the space thus left 
open, Neevia had renewed her web. (Fig. 208.) The tube was in the cor- 
ner, and of rather feeble character, but the pouch was doubled up some- 
Agalena’s 
Trestles. 
S= A a | | 
i SS 
<= 
= 
Aner 
[\\ 
SH ANY 
Fic. 209. Agalena’s web with suspension lines and trestles between the bars of a fence. 
thing like a roll, and extended entirely across the window. For about two- 
thirds of the way it was an ordinary sheeted snare. Then it flared upward 
and was attached to the upper part of the window frame, and was contin- 
ued to the opposite side of the window with rather straggling lines. As 
though to support this structure at either end, a series of strong and very 
straight taut brace lines was extended downward from either end as shown 
in the figure. No conclusion is possible except that this was done for the 
purpose of staying the drooping pouch of the snare, and this, of course, 
implies intelligent engineering. 
The example cited is only one of many which might be presented 
from my somewhat extended and varied studies of the Speckled Tube- 
So en a 
