THREADS OF SPII>ERS. 
367 
if the spider was small, carried up to the roof of the room, 
or to a high part of the wall. They often did this when 
made to drop, by a slight shake from the point of the 
finger; and I have observed this happen so late in the even- 
ing, and in such very cloudy weather, either in the still 
air of an apartment, or in the open air when serene, that I 
do not consider that the ascent was caused by the rarefac- 
tion of the lower atmosphere. 
I have noticed four different species of spiders that have 
the faculty of emitting their threads in this curious man- 
ner. 1. The garden spider from the time it emerges from 
the nidus ; — A spider of a light brown colour which I 
have not yet seen described : It is not shaped like the 
young of the house-spider, nor does it attain to a third of 
its size, but it is larger than the gossamer spider : It 
weaves a very thin web ; — 3. The gossamer spider ; and 4., 
a small green-bodied, fiat spider, which has not yet, I be- 
lieve, been properly described. It is somewhat of the form 
of the sheep tick, with short dark brown legs, and is usually 
found amongst stones and old walls ; it is very fierce, beat- 
ing off spiders of three times it own size. It is not to be 
confounded with a green-striped spider, for they are quite 
distinct ; the latter being sluggish and weak, with long 
white legs. I should also be inclined to think that the 
Aranea diadema had this power *. 
There appears still to exist a considerable difference of 
opinion amongst entomologists, in respect to the power the 
spider has of directing the thread it ejects to any particular 
spot to which it is desirous of attaching it ; and also as to 
its capacity of ascending into the air, by the buoyancy of 
the long line it emits. 
" Mr White, in his Natural History of Selborne, and Mr Murray 
of London, in his Experimental Researches, has made several inte- 
resting observations on the power the gossamer spider possesses of 
raising itself into the air. 
