THE SNARE OF THE GIANT WOOD SPIDER. 
921 
It was proved by the ingenious experiments of Fabre why a geometrical spi- 
der does not become entangled in its own snare. He discovered in his usual 
simple way that on the integument of the spider there was an oily film, and 
that, owing to the presence of this unctious coat, the architect did not adhere 
to her own lines. It was a simple matter to substantiate this. 
By means of disulphide of carbon the oily film was dissolved away ; and then 
the spider, like any oi-dinary substance, adhered to the sticky filaments of 
the snare. I have had the opportunity of repeating these experiments, and 
they led me to the same result. 
But a point which did not come vathin the observation of Fabre was how and 
where this oily film is produced. At first it might naturally be suspected that 
the oil was some kind of a cutaneous secretion which oozed out from the spi- 
der’s skin ; but when we consider the character and structure of the integument 
it is difficult to understand from where the secretion could appear. We can 
scarcely imagine glands in the hard coat of a spider in any way like those in the 
human skin. But speculation on the matter is needless ; the Nephila supplies 
an excellent opportunity of obser%ing the source from where the film is derived. 
It occurs in this waj. The sim has almost set, and the Nephila is hanging 
suspended from a single line. Her snare has already been cut away, and the 
hour has not 3’’et come for her to commence the architecture anew. Her legs arc 
stretched out round about her ; one, of course, is fixed to the suspension line, 
and, in this attitude, she hangs stationary in the air. I see her now from time 
to time act in a very deliberate way. She slowdy carries a hind leg forward 
and carefully inserts the tarsus into her mouth. It is placed lengthways be- 
tween her jaws, and the palpi secure it on either side. It is held there for a little 
while ; it is thoroughly moistened with a clear secretion, squeezed out, I sup- 
pose, from the salivary glands ; indeed I can even see a drop of the liquid oozed 
out between the spider’s jaws. The tarsus is then withdrawn ; it is carried 
backward, and, while still wet with the secietion, it is gently stroked over the 
tip of the abdomen romid about the cluster of the spinnerets. I now see another 
leg brought in the same determined manner to the mouth. It likewise is mois- 
tened with secretion, then withdrawn, and then employed as a kind of brush 
along the full length of one of the opposite limbs. Then another change fol- 
lows. A third leg is taken to the mouth, and the same procedure occurs. In 
this behaviour the Nephila persists, all the while suspended from a thread. 
She brings each leg repeatedly and in succession to her mouth, moistens it, ex- 
tracts it, and then transfers the moisture elsewhere. It is a very slow and metho- 
dical operation, an act full of purpose and decision. Now what does it mean, 
for it is clearly a work of much importance ; it is so slow, so persistent, and I 
see her engaged at it for over an hour ? 
Its purpose is this. The Nephila is smearing her body with oil in order to 
prevent her sticking to the snare. She w'ill commence the ffist stages of construc- 
tion soon ; this is the prehminary to the work. Her oil, therefore, is no cutaneous 
secretion ; there are no delicate hair-glands, no minute perforations, that open 
on the surface of the skin. It is from her sahvary glands that she obtains the oil, 
and she applies it to the various parts of her body by means of her own legs. 
Now watch again with a Httle care. There are a few further points to note. 
She does not smear the secretion everywhere so as to cover her whole body in a 
film. She shows far greater care and discrimination than this ; it is offiy to 
certain particular parts that she applies her layer of oil. It is no doubt a pre- 
cious substance of which she has no profuse supplj’, she must therefore work 
with providence and apply it only where required. She pays most attention 
to her legs. Each tarsus, of course, is oiled in the mouth but she is also very 
careful to paint the legs throughout their whole length. For this purpose one 
tarsus is often carried across so as to smear a shank on the opposite side. 
Another point that gets much attention is the ventral surface of the tip of the 
