174 THE WONDERS OF INSTINCT 



an artist initialing his creation. u Fecit So-and-so/' she 

 seems to say, when giving the last throw of the shuttle 

 to her handiwork. 



That the Spider feels satisfied when, after passing and 

 repassing from spoke to spoke, she finishes her spiral, is 

 beyond a doubt : the work achieved ensures her food for 

 a few days to come. But, in this particular case, the 

 vanity of the spinstress has naught to say to the matter : 

 the strong silk zigzag is added to impart greater firmness 

 to the web. 



The Lime-snare 



The spiral network of the Epeirae possesses contriv- 

 ances of fearsome cunning. The thread that forms it is 

 seen with the naked eye to differ from that of the frame- 

 work and the spokes. It glitters in the sun, looks as 

 though it were knotted and gives the impression of a 

 chaplet of atoms. To examine it through the lens on the 

 web itself is scarcely feasible, because of the shaking of 

 the fabric, which trembles at the least breath. By pass- 

 ing a sheet of glass under the web and lifting it, I take 

 away a few pieces of thread to study, pieces that remain 

 fixed to the glass in parallel lines. Lens and microscope 

 can now play their part. 



The sight is perfectly astounding. Those threads, on 

 the borderland between the visible and the invisible, are 

 very closely twisted twine, similar to the gold cord of our 

 officers' sword-knots. Moreover, they are hollow. The 

 infinitely slender is a tube, a channel full of a viscous 

 moisture resembling a strong solution of gum arabic. 



