390 CLASS ARACHNIDA. 



biated cleft, as in the Micrommata argelas ; sometimes it is 

 sheltered by a prolonged operculum, and terminated like a 

 tail, as in the Epe'ira diadema ; or it sometimes presents itself 

 in the form of a tubercle. 



With respect to the simple eyes, the same observer remarks, 

 that they shine in darkness, or dusk, like those of the cat, and 

 that the araneides have probably the faculty of seeing both 

 by day and night. 



The abdomen of the araneides putrifies and changes after 

 death to such a degree, that its colours and even its form be- 

 come undistinguishable. M. Dufourhas succeeded, by means 

 of a very prompt desiccation, of which he explains the process, 

 in remedying this inconvenience. 



According to Reaumur, the silk undergoes a first elabora- 

 tion in two small reservoirs, having the figure of a Rupert's 

 drop, placed obliquely one on each side, at the basis of six 

 other reservoirs, shaped like intestines, situated one at the side 

 of the other, bent six or seven times, setting out a little below 

 the origin of the belly, and leading to the nipples by a very 

 slender thread. It is in these last vessels that the silk acquires 

 more consistence and the other qualities which are peculiar 

 to it. They communicate wdth the preceding by branches, 

 forming a great number of bends, and then divers interlacings. 

 On proceeding from the nipples, the silken threads are glutin- 

 ous ; a certain degree of desiccation or evaporation of moisture 

 is necessary before they can be employed. But it appears, 

 that when the temperature is propitious an instant is sufficient, 

 since these animals make use of them almost immediately as 

 they escape from their spinnerets. Those white and silky 

 flakes which we see flying about in spring and autumn, on 

 days in w^hich there has been a fog, and which are vulgarly 

 termed " the virgiii's threads^'' are certainly produced, as we 

 have been convinced by following them from their point of 

 departure, by divers young araneides, and especially by Epe'ira) 



