J2 GENERATION OF INSECTS 



been broken, is able to make his web. Father Blancano 

 asserts that he has ascertained by experiment that the 

 spider's thread is not simple and smooth, but is composed 

 of many fine strands, so light that they float out in the 

 air, in all directions, and catch in the branches of nearby 

 trees, of which circumstance the spider quickly avails 

 himself to make fast the first lines of the future web. 

 This is possible, provided that the spider hangs down 

 from a high tree. I have not had occasion to observe 

 this, though I have frequently seen the spiders stretch 

 their thread from one part of the highway to the other, 

 and attach the ends to the tops of the stakes that support 

 the vines, but since these stakes are not higher than 

 three or four yards, and the road is at least eight or ten, 

 wide, I cannot see how the spiders, from so low a height, 

 could acquire sufficient force to give the principal thread 

 the required length, so that the lateral filaments could 

 reach the other side of the road. Everyone may think 

 as he chooses about this; for my part I must return to 

 my preceding argument and tell you that I collected a 

 large quantity of spiders, and, having killed them, left 

 them in a large, open dish, whither the flies eagerly 

 swarmed to feed and to deposit their maggots, almost 

 vengefully, so that the dead spiders soon became wormy, 

 and the w^orms having hardened into eggs or chrysalides, 

 from these flies hatched out, such as daily circle about 

 our houses. 



Leaving this subject for the present, as it seems to be 

 sufficiently proven that flesh does not become wormy of 

 itself, I deem it time to pass to the consideration of other 

 things that have been supposed to produce worms; this 

 opinion being held not only by the common people, but 

 even by men of science. One of the most important 



