148 A NATURALIST IN HIMALAYA 



swallowed the flies. Camphor is a germicide and 

 injurious to insect life, and I have no doubt that it 

 would be equally harmful to spiders. I have before 

 mentioned how certain ants are instantly driven away 

 by the odour of camphor, but the Araneus passed it 

 unobserved. It did not seem to recognize the strange 

 substance, and I doubt whether it possesses any more 

 than a rudimentary sense of smell. 



I believe a spider often sees the flies becoming 

 entangled in its snare. It does not work by the power 

 of touch alone. I feel sure that an Araneus^ which I 

 once observed descend to attach the vertical line of its 

 snare, was able to detect the presence or absence of a 

 suitable anchorage from a point eight inches above the 

 surface of the water. I have seen an Araneus rush 

 out along a radius in the endeavour to catch a fly that 

 came dangerously close to, but did not touch the snare. 

 Also I observed a spider drop down from the centre 

 of its web to a distance of about three inches in order 

 to seize a fly passing underneath. In both these 

 cases, however, the stimulus may have affected the 

 sense of hearing rather than that of sight. 



Touch, I am sure, is the most accurate and sensitive 

 of all the senses. It is by touch that a spider ensures 

 the shape, the structure, and the symmetry of its 

 snare. Its limbs are rule, compass and dividers with 

 which it weaves its perfect plan of architecture. More- 

 over, it is ambidextrous, measuring with either limb 

 as it circles to right or left. It is by touch that it 

 discovers the entanglement of its prey. Another 

 spider far away on the external frame is instantly 

 felt and distinguished from a captured insect. Imitate 

 how you will the entanglement of a fly, you cannot 



