GENERAL CHARACTERISTICS OF ORBWEAVERS SNARES. ol 
‘ 
movements there, always when capturing an insect, and often in bringing 
the captive to the Hub, do at times result in the marring and breakage 
of the snare. ‘The fact that the prey are taken to the centre to be fed 
upon and sometimes to complete the swathing is a reason why that por- 
tion of the web should not be covered’ with viscid beads, which are obvi- 
ously a hinderance to feeding upon and 
swathing the victim. In fact the viscid 
parts have to be cut out in order to per- 
mit the revolving of the captured prey 
when it is being swathed. 
2. Moreover, the struggles of insects en- 
snared upon the beaded spirals, and subse- 
quent actions of the spider to capture its 
prey, invariably break up more or less of 
the web. In the case of large insects the 
damage done is quite serious. Were the 
Central space also beaded it is evident 
that the very seat and throne of the 
aranead at the hub of the snare would 
be greatly liable to invasion, to her sore discomfort and disadvantage, 
especially in cutting off her avenues of approach to the main portions 
of the snare. ‘This would be no less true in cases where her retreat 
is a leafy or silken castle outside the limits of the orb but connected with 
the hub by a trapline. The breaking of the radii at the point of their 
: attachment to the hub of course must cause all 
the connected parts towards the circumference 
to relax, entangle, and drop away. Repair in 
such cases is difficult or impossible. The far- 
ther from the centre is the point at which the 
insect is entangled, the less injury ensues, the 
longer does the web remain seryiceable, and 
the more easily is it mended. Thus, the ab- 
sence of beads from the entire Central space 
gives added security to the snare. 
3. In like manner the economy of the Free 
zone may be considered as protective. The ab- 
Fig. 55. Semiciroular zigzag cords in sence of spiral’ lines enables many insects to 
the hub of Argiope. “ i 5 
pass quite through the net, with little or no 
impediment. When there is a momentary arrest or entanglement, the 
subsequent escape or capture is accompanied by very slight, if any, de- 
struction. 
4, Here, too, it may be observed that the necessity for viscid beads near 
the centre is not as manifest as upon the outlying parts. The momentary 
pause caused by an insect striking upon the naked radii of the Free zone 
Fic. 54. The ribbon brace of Acrosoma. 
