THE SNABE OF THE hIA^T WOOD SlUDER. 
917 
’n her architecture unless her temporary spiral be an extended hub. The tem- 
porary spiral of the Araneus is a wide-open structure ; the Nephila weaves a 
close-wound coil. Four turns are enough for the Araneus, and they are confined 
to the inner half of the snare ; the Nephila makes over forty circles spread from 
the centre to the rim. The temporary spiral serves the Araneus for the purpose 
of a bridge ; the Nephila steps from spoke to spoke. In the snare of the Araneus 
it is subsequently destroyed ; the Nephila retains it permanently to the end. 
The viscid spiral of the Araneus is uniform through the snare ; the Nephila 
intermingles it with her temporary coils. The fore leg of the Araneus measures 
the distance between its lines ; the Nephila makes use of her hind leg to secure 
a similar end. The architecture of the Araneus takes half an hour ; the Nephila 
works for half a night. 
We have finished. We have watched the Nephila through the lonely hours, 
and we leave her now to take her station in her snare. The long night is over ; 
we even see the first faint streak of dawn. Let us go, satisfied with what we 
have seen. There are none who would join us in this silent vigil, yet the hours 
are not altogether lost. We have learnt something of beauty and of wonder 
from this marvellous geometrical snare. 
P.ART III. 
Further Lessoxs of the Xephila. 
I will now consider some further lessons taught us by the architect of this 
snare. We must take every opportunity to learn from one who is so large and 
so leisurely at her woi-k. 
The first is a matter in respect to he r architecture. It concerns what I have 
elsewhere described as the “ reversal of the spiral.” It is only on rare occasions 
that a little spider, such as the Araneus, will construct a viscid spiral of one 
single line continuous from end to end. That is the ideal nuthod, but in actual 
practice she has to modify the work. If we observe her with reasonable care 
we ■will often see the following occur. She is anchoring her 'vdscid spiral; all of a 
sudden she halts ; she seals off the end of her spiral ; she turns about and commen- 
ces a new spiral by circling in the opposite way. Moreover, we rvill observe that 
she always adopts this behaviour when the point from where her radii diverge 
happens not to coincide ■with the true centre of the web. On those occasions 
some of the radii happen to be long, others happen to be short. And the 
reversal, we observe, is a plan of architecture associated with the eccentricity 
of the snare. Furthermore, we will observe that she so arranges her reverses 
that their effect is to add additional turns to the long radii, and in this way make 
up for the eccentric nature of the work.* 
The Nephila adopts a similar plan. I have found certain of her immense 
sheets in which the so-called centre was very eccentric. I recall one of over five 
feet in diameter where the centre was only eight inches from the upper edge. 
While employed in the architecture of so eccentric a work the Nephila must 
reverse at almost every turn. If she circled in the ordinary way round and 
round her snare, she would very soon complete her spiral in the short and upper 
spokes, while the long and lo^wer ones would be almost empty of threads. To 
prevent this she must repeatedly reverse so as to keep her thread almost confined 
* The reversal of the spiral is discussed in detail in “ A Xaturalist in Himalaya.” 
