i3§ 
Psyche 
[September 
very large web. The arguments dependent on the effects of klepto- 
parasites are not easy to resolve. We have seen prey stolen from 
the hub, during the absence of the spider, on many occasions. We 
have also seen N. clavipes respond to, attack, and eat, kleptoparasites 
that were moving about near to the periphery of the web. Other 
hypotheses to explain the absence of capture-site food storage by 
N. clavipes include the possibility that this spider has not evolved 
a sufficiently efficient wrapping technique to safely allow the storage 
of prey in situ , or that the presence of prey packages in an already 
fine meshed web might render it more conspicuous, and hence 
avoidable, to flying prey. 
It seems worth stressing the fact that N. clavipes can be induced 
to wrap prey in situ if these are made difficult to remove from the 
web by pulling. This simple function of post immobilization 
wrapping at the capture site may have been obscured by the fact 
that such wrapping can serve other functions in the predatory 
strategy of other araneids. The function of simplifying the safe 
removal of prey from the web seems to us, on a priori grounds, to 
be basic and probably primary. Similarly the existence of free- 
wrapping behavior suggests that the trussing or packaging function 
of wrapping is an important one in its own right, and not merely 
the useful by-product of a process serving another function. Both 
these opinions derive from our study of the behavior of N. clavipes, 
and, as far as we know, were not anticipated by earlier studies of 
more “advanced” araneids. 
If we now consider the model shown in Figure I our earlier 
comment that this represents a very considerable simplification can 
now be expanded. We have detailed some of the behaviors that are 
not included in the model on pp. 132- 134. In our account of the ex- 
perimental side of our studies it is obvious that the investigation of the 
effect of external stimuli on the course of predatory sequences is not 
complete. Although we have shown that some behavior units can 
be brought into play in response to simple stimuli we have not 
shown that these are the only effective stimuli in all cases. We 
have made no progress at all in investigating the effect of internal 
factors on the behavior of the spider. In all these respects the 
model is inadequate, although it is already quite complex. 
We have also ignored any discriminations that may be involved 
in the termination of acts of behavior after they are brought into 
plav. The spider must, for instance, both start and stop the process 
of bite & back off, and start and stop the process of pulling out the 
prey. Peters ( 1931, 1933a, 1933b), in elegant studies of the behavior 
