THE ARACHNIDA. 301 
with great care, so that there are as many above as in 
the cup. It then finishes spinning the cocoon. 
512. The Caterpillars spin from the head, but the Spi- 
der spins from the other extremity of the body. Its spin- 
ning apparatus is of peculiar construction. Inside is a 
reservoir of gummy matter from which the silk is made. 
The threads of a Spider’s web are drawn out from it, 
and dry as fast as they are drawn. But the thread, which 
appears to the eye as single, is found by the microscope 
to be composed of many thousands of threads united to- 
gether. In ee 234 you see, as the Spider hangs by his 
thread, that it comes 
out from a circular 
? spot. In this are four 
and sometimes six 
knobs, which can be 
seen by the naked eye. 
Kach of these is full of 
holes through which 
the threads come, and 
these holes are so mi- 
nute that Reaumur cal- 
> = 
eg: fi 
i! 
a i DS “culated that a thou- 
IK AIS ‘s sand occupied a space 
y) ae no larger than the 
‘ A point ofapin. In Fig. 
235 (p. 302) is repre- 
ae: 2 sented such a view of 
these knobs as you would get by a powerful microscope. 
A portion only of the minute threads are represented. 
It was the calculation of Leuwenhoeck that it would 
take four millions of them to make a thread as large as a 
hair. 
513. These threads are united together about one tenth 
of an inch in distance from the spinnerets. By this sep- 
arate exposure to the air of each threadlet, they all be- 
come dry before their union. Another advantage of this 
