RESEARCHES UPON SPIDERS. 63 



But without seeking the American spiders, we have, 

 and I have myself found in this country, the spiders which 

 Pallas calls Aranea speciosa, and which Razomorsky calls 

 Aranea jndchra, which make such cocoons that three alone 

 not cleansed, and five free from all impurities, weigh as much 

 as one cocoon of the common silk-worm. I will also add, 

 that having, during this year, verified my observations on the 

 cocoons of the diadema spiders, I have found constantly that 

 vsix of these, and not twelve as Reaumur would have it, are 

 equivalent to one cocoon of the silk-worm. 



But even less than six are sufficient. I have observed 

 that if I take the cocoon from the spider, when it is hardly 

 formed, and take the eggs from it, the cocoon, which I call 

 then the virgin cocoon, remains very clean, and since it 

 loses nothing, it is so heavy that only four are equivalent to 

 one cocoon of the silk-worm. In this way, in order to pro- 

 duce a pound of silk > there will not be required, as Reaumur 

 says, more than 55296 cocoons of the spider, but 13825 will 

 suffice. In order to show the advantage which the silk-worm 

 has over the spider, Reaumur observes that among spiders 

 the females alone make the cocoon, whereas, among silk- 

 worms, the males produce as many as the females; whence, 

 considering the number of individuals of the two sexes to 

 be equal, he supposes that double the number of spiders is 

 required for an equal number of cocoons. But beside that 

 his supposition is not true, as we shall see, he does not ob- 

 serve that the silk-worms give but one cocoon a year ; whereas 

 the female spiders give even six as already stated. Reau- 

 mur was ignorant of that, although Lister' had previously 



all the others which contain the eggs of spiders. We ought not to wonder, 

 says Lyoniiet, speaking of other mistakes taken from Mademoiselle Merian, 

 that in this a lady may be deceived who is more intent on drawing well, than 

 on studying insects. Besides, in a foreign country, it is natural to believe 

 the natives in regard to common objects. I even put faith in the Indians, 

 who gave me to understand that the wood of their arrows was very hard, 

 because, putting it in the fire, it could be drawn out and, being compressed, 

 lengthened, acquiring thus compactness and strength. I published that in 

 good faith (Opusc. Sulti. pag. 377, nota) but being informed of my error by 

 my colleague, who has studied the arts of the Indians more than I, I volun- 

 tarily confess and retract it. 



