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Psyche 
[December 
the case of Argiope argentata (Fabricius) during a study involving 
the examination of 2614 adult webs of this species (Robinson & 
Robinson 1970: 644). Examination of our unpublished data on the 
nature of skeleton webs shows that they were not simply old webs 
but constructions with a small number of radii, no viscid spiral and 
no well-defined structural spiral. Stabilimenta in such webs were 
extremely long, had widely spaced zig-zags and frequently had areas 
where the stabilimentum silk was deposited on top of a single radius. 
Thus the constructional details of these stabilimenta were strikingly 
parallel to those seen in the stabilimenta found in skeleton webs of 
N. clavipes. This can be seen by comparing Figure 2 herein with 
Figure 3 of Robinson & Robinson (1970: 646). In our study of 
Nephila maculata we found adult females ceased web renewal several 
days before egg-laying but remained on old, or skeleton, webs (Rob- 
inson & Robinson 1973). We now suspect that the examples of 
skeleton webs that we found in Argiope argentata were constructed 
by females that were about to lay eggs and that in both cases these 
webs function as resting platforms at a stage when food capture has 
become unnecessary. In the case of Nephila clavipes the skeleton 
webs of immature females almost certainly function as moulting 
platforms. (We were fortunate to see one female ecdyse whilst on 
a skeleton web and found two others with cast cuticles still present.) 
The spider moults below the web, hanging on a silk line attached 
to its hub. When moulting is complete, the spider eventually swings 
back onto the skeleton web and assumes a normal predatory stance. 
The skeleton webs of Nephila clavipes that we examined (22) 
were characterized by small area (compared with the perfect webs 
of the same developmental stage) and the small number of radii that 
were present. The hub regions appeared to be normal and barrier 
webs were present in all cases. Strong (thick) bracing threads 
connected the hub region to one or other of the barrier webs, or 
sometimes to both of these structures. Such threads are present in 
most of the webs of Nephila clavipes and produce a conical distortion 
of the hub above the spider’s resting area. In this region there are 
often deposits of sheet silk laid down irregularly over the hub ele- 
ments and base of the bracing line(s). Of the 275 webs that we 
censussed, 80.7% had conspicuous silk deposits on this region. The 
significance of this aspect of web structure is discussed below. 
Discussion 
Three central (and related) questions result from our study of 
the stabilimenta of Nephila clavipes and N. maculata: 
