SPIDERS, 353 



throw out a single inch of thread without the aid of 

 a current of air, A long-bodied spider will thus 

 throw out in succession as many threads as we please, 

 by simply blowing towards it; but not one where 

 there is no current, as under a bell-glass, where it 

 may be kept till it die, without being able to construct 

 a bridge over water of an inch long. We never 

 observed more than one floating thread produced at 

 the same time; tliough other observers mention 

 several. 



The probable commencement, we think, of the 

 floating line, is by the emission of little globules of 

 the glutinous material to the points of the spinnerules 

 — perhaps it may be dropped from them, if not 

 ejected, and the globules being carried off by the 

 current of air, drawn out into a thread. But we give 

 this as only a conjecture, for we could not bring a 

 glass of sufficient power to bear upon the spinnerules 

 at the commencement of the floating line. 



In subsequent experiments we found, that it was 

 not indispensable for the spider to rest upon a solid 

 body when producing a line, as she can do so while 

 she is suspended in the air by another line. When 

 the current of air also is strong, she will sometimes 

 commit herself to it by swinging from the end of the 

 line. We have even remarked this when there was 

 scarcely a breath of air. 



We tried another experiment. We pressed pretty 

 firmly upon the base of the spinnerets, so as not to 

 injure the spider, blowing obliquely over them; but 

 no floating line appeared. We then touched them 

 with a pencil and drew out several lines an inch or 

 two in length, upon which we blew in order to extend 

 them, but in this also we were unsuccessful, as they 

 did not lengthen more than a quarter of an inch. 

 We next traced out the reservoirs of a garden- 

 spider (Epeira diade^na), and immediately taking a 



VOL, IV. 30* 



