STRUCTURE AND ECONOMY OF SPIDERS. 295 
can seldom be seen to advantage unless artificial light 
be employed, some skill in the management of which 
is required in order to avoid disturbing the spider. 
The modus operandi, as nearly as 1 can ascertain it 
by the most diligent observation, appears to be this. 
The points of the lower row of spines in passing over 
the extremities of the mammulz draw from them lines 
which run into numerous flexures in consequence of 
not being kept fully extended ; and the purpose sub- 
served by the upper row of spines seems to be the 
detachment of these lines from the spines of the lower 
row by a motion upwards. Now, were the blue 
bands glutinous, this mode of proceeding would be 
quite unavailing ; it is only on the supposition, there- 
fore, that they have a fibrous structure that their 
adherent property can be satisfactorily explained. 
When a sufficient quantity of the inflected filaments 
is produced, the spider again applies its spinners to 
one of the glossy lines, and attaches the flocculus to 
it. In this manner it proceeds with its labours, 
occasionally employing both calamistra, till the snare 
is completed. Should many of the flocculi be de- 
stroyed, or rendered almost useless by having their 
adherent property impaired, new ones are constantly 
added to the snare. 
The admirable adaptation of the structure and dis- 
position of the calamistra to their action on the 
spinners, by which, under the directing influence of 
instinct, the curious snare of Ciniflo atrox is perfected, 
