84 A NATURALIST IN HIMALAYA 



Though foreign to the usual habits of spiders, these 

 two species live together in perfect harmony. Most 

 spiders prefer a solitary existence, desiring no com- 

 panions, devouring every intruder or driving it savagely 

 away. Yet these spiders often follow a gregarious 

 life, interweaving their snares into one wide common 

 sheet. It is not unusual to find half a dozen of these 

 snares all connected by their foundation-lines, and 

 even those of the two species sometimes intermingle. 

 I once found a collection of twenty-one snares all 

 communicating one with the other, and both Araneus 

 and Tetragnatha were represented in the colony, and 

 they all lived together in complete harmony. Spiders 

 in other countries sometimes unite into similar com- 

 munes. Darwin tells us that in South America a 

 species of Epeira congregates in small colonies so as 

 to encompass large bushes with their united nets. He 

 remarks on the singular fact that this gregarious habit 

 should exist in such bloodthirsty and solitary creatures. 

 Peace exists in these colonies over the streams. The 

 spider from one snare seldom invades that of its 

 neighbour ; should it by mistake cross the frontier, it 

 is immediately made aware of its error and ordered to 

 be off. For the spider in the invaded snare throws the 

 whole structure into a state of rapid vibration, and the 

 intruder, feeling this, instantly turns about and returns 

 to its own territory. 



From year to year the numbers of these spiders 

 vary. A dry summer results in a scarcity of insects, 

 and this is a direct cause of the rarity of the spiders. 

 A wet season supplies an abundance of snares. And 

 not only are the spiders affected through the medium 

 of the insects, but so also are the insects that prey on 



