ON ARACHNIDA. 443 



towards their extremity, they terminate in a straight thread, 

 leading to the nipples, which are cylindrical or conical parts, 

 and membranaceons, serving as a conduit to the threads of 

 silk, which are named spinnerets. 



The mygala) have but four apparent nipples, the upper two 

 of which form a small forked tail ; but in the others they are 

 six. In these the nipples have but two articulations, the last 

 of which, in the form of a head, is bordered all round, like a 

 crown, with several conical pieces, which give issue to the 

 silken threads, and are in fact the spinnerets properly so 

 called. 



The proper spinnerets of each nipple are carried by some 

 authors to the number of a thousand, so that, when all the 

 nipples are at work, the quantity of threads which proceed 

 from them should be six thousand. But these animals manage 

 with economy a substance which constitutes a portion of their 

 means of existence, and which is also necessary to the preser- 

 vation of their posterity. Moreover, this calculation is not 

 applicable to all the species, since many of them form no web, 

 and employ their silk only in the construction of the cocoon, 

 which is to envelope their eggs. 



It has been attempted, by weaving, to derive some advantages 

 from the silk of certain of the araneides of the genus epeira, and 

 gloves and stockings have been made of this silk, of a greyish 

 colour, almost as strong as those fabricated with the ordinary 

 silk. Lebon employed that of the cocoon of these animals, 

 and thirteen ounces of these cocoons yielded four ounces of 

 silk. To put it into a state for being wove, he caused it to be 

 beaten with the hand, and with a small stick, for the purpose 

 of expelling the dust ; he afterwards washed it in tepid water, 

 and put it then into soap-suds, in which some saltpetre and 

 gum-arabic were dissolved. The whole was kept boiling over 

 a slow fire for two or three hours, and the cocoons after this 

 operation w^ere washed in tepid water, until they yielded to 

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