420 FOOD OF INSECTS. 



In this renewal, as above hinted, the geometrical spi- 

 ders are constantly regulated by the future probable 

 state of the atmosphere, of which they have such a nice 

 perception, that M. Q. D'Isjonval, to whom we are in- 

 debted for the~ fact, has proposed them as most accurate 

 barometers. He asserts that if the weather be about to 

 be variable, wet and stormy, the main threads which sup- 

 port the net will be certainly short ; but if fine settled 

 weather be on the point of commencing, these threads 

 will be as invariably very long a . Without going the 

 length with M. D'Isjonval of deeming his discoveries im- 

 portant enough to regulate the march of armies, or the 

 sailing of fleets, or of proposing that the first appearance 

 of these barometrical spiders in spring should be announ- 

 ced by the sound of trumpet, I have reason to suppose 

 from my own observations that his statements are in the 

 main accurate, and that a very good idea of the weather 

 may be formed from attending to these insects. 



The spiders which form geometrical nets differ from 

 the weavers also with respect to the situation in which 

 they watch for their prey. They do not conceal them- 

 selves under their net, but are placed in the centre with 

 their head downwards, and retire to a little apartment 

 formed on one side under some leaf of a plant, only when 

 obliged by danger or the state of the weather. The mo- 

 ment an unfortunate fly or other insect touches the net, 

 the spider rushes towards it, seizes it with her fangs, and 

 if it be a small species at once carries it to her little cell, 

 and, having there at leisure sucked its juices, throws out 

 the carcase. If the insect be larger and struggle to escape, 

 3 Brez, La Flore des Imedojilnies, 129. 



