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SUPPLEMENT 
according to the same author, has accorded to each spider a 
sufficient quantity of the silky matter to make six or seven 
webs during its life. When no more remains, they must either 
die, or appropriate to themselves the production of others. 
The life of many species scarcely extends beyond the term 
of eight or twelve months. But the mygales, the spiders 
properly so called, and the lycosse, can live many years. 
Many pass the winter shut up in holes concealed under 
stones. Some even construct for themselves, in that season, a 
cocoon of silk, which serves them as a retreat. 
In the fine days in autumn, we may see floating in the air 
a tolerable quantity of threads of silk, which are often carried 
by the wind to a considerable height. Many of these threads 
are the work of some young araneides ; of this we may convince 
ourselves by examining them closely. We shall find at one of 
the ends, little spiders occupied in producing new threads, 
or elongating those which have been already spun, until they 
are fixed at a distance to some solid place, whither they can 
transport themselves. 
Quatremee dTsjonval believed that he discovered in the 
epeirse, a natural barometer; but it does not appear that this 
opinion has been followed up, or has led to any results. 
The spiders of the genus Mygale appear to be nocturnal 
animals. Their sombre colours, and some observations which 
have been made upon them, seem to authorize this conjecture. 
They establish their domicile in cavities usually subterraneous, 
which they either prepare for themselves or find by chance, 
and whose aperture they line after the manner of the tubicolse, 
which are likewise nocturnal animals. 
In this genus are found those monstrous araneides which 
can occupy a circular space of from seven to eight inches in 
diameter, and w hich sometimes even seize small birds. 
These species are in general peculiar to the equatorial 
countries, and those which border on the tropics. They are 
