378 ARACHNIDA—ARANEAE CHAP. 
genera, were offered to them, they appeared equally satisfied, and 
attached them in the orthodox manner, beneath the abdomen. 
The same treatment was even accorded to pith balls, which, if of 
the right size, seemed to be a perfectly satisfactory substitute. 
The contents of one cocoon were replaced by a shot three or four 
times their weight, but the spider accepted it with alacrity, 
spending half an hour in refixing it, when its weight caused it 
to fall from its attachment. 
The habit of “feigning death,’ which seems to be especially 
characteristic of the Epeiridae or orb-weaving spiders, probably 
arises from no desire to deceive its adversary as to its condition, 
but from an instinct to remain motionless, and therefore incon- 
spicuous. Where a nomadic spider seeks safety in flight, a 
sedentary species finds a greater chance of escape in dropping a 
certain distance, and, while still attached by its silken line, giving 
as little evidence of its whereabouts as possible—trusting, in 
many cases, to its protective colouring. This method, moreover, 
has the advantage of facilitating its return to the web when the 
danger is past—a feat of which it would be quite incapable were 
it once to relinquish its clue. 
All the remarkable and apparently intelligent actions of these 
creatures seem to be done in obedience to a blind instinct, which 
is obeyed even when there is no longer any object to be served. 
We have seen how the Trap-door spiders decorate the lids of 
their nests with moss even when the surrounding ground is_ bare, 
and Agelena labyrinthica has been observed to go through the 
whole lengthy and laborious operation of constructing its egg 
cocoon though all its eggs were removed immediately on being 
laid. | 
Mating Habits——The sex of a mature spider can readily be 
recognised by the palpus which, as we have seen, is furnished in 
the male with a “palpal organ.” After the last moult but one 
the palp appears tumid, but it is only at the last moult that the 
organ is fully formed, and that the genital orifice is visible under 
the anterior part of the abdomen. 
No alteration takes place in the female palp at maturity, but 
it is only after the last moult that the “ epigyne ” is distinguishable. 
That the palpal organs are used in the fertilisation of the 
female has long been established. How they came to contain 
! Warburton, Ann. Nat. Hist. (6), viii., 1891, p. 113. 
