Akaohnida. INSECTS. Abaohneda. 
cclxxiv 
teriiig' on tlie sides of the excavation he digs a large 
liole, and tlieii coniineiices at tlie bottom to build a 
wall of mud, which on completion forms a tul)e. 
'I’his is lined with silken threads, woven so as to 
hold the material and render the nest impervious to 
dampness. At tlie lower end there is a small open- 
ing sufBcient to let off any water that may get in 
IVom the top. 
'I'here are four principal types of trap-door nests; 
two of them exhibit two doors each, one door being 
some distance underground, while the other is always 
on the surface. All are constructed under ground in 
an excavation made by the creature, and in eveiy case 
lined with silken threads, which are so closely woven 
as to resemble the finest satin. In one instance, that 
of the West Indian species, the door is wholly con- 
structed of silk, without admixture of earth, lying on 
rather than fitting into the ajierture of the tube. In 
others the door is made of the same ma terial as the 
tube, of layers of earth and silk, and so contrived that 
it fits closely like the stopper to a bottle, the mouth 
of the tulle being bevelled to receive it. The Spider 
builds this interesting dwelling by first excavating a 
hole in the earth, which is carefully fashioned to a 
cylinder shape; with her jointed fangs she carries 
the bits of earth out as they are dislodged. 'I’he 
silk is now spun out and attached on all sides, form- 
ing an even continuous lining. 'I'he mouth of the 
tube is dilated a little to allow of the close fitting of 
the trap, which is hinged very delicately by a woven 
patch of silk. Within the tube and near the upper 
portion are minute punctures which have puzzled ob- 
servers. Mr. Grosse is inclined to think that in the 
case of the West Indian specimens, which he observ- 
ed, they were made to give air to the otherwise air- 
tight cavity. Others think they are simply the re- 
sult of a hold which the Spider exerts while defending 
the entrance from intruders. Nests are almost inva- 
riably placed on sloping ground, so that the door 
may fall by its own weight when opened. Much dif- 
ference of opinion exists concerning the action of the 
Spider when assailed from without. 
Mr. Moggridge, in his work on Traj>door Spiders 
and Harvesting Ants, says : “ No sooner had 1 gent- 
ly tapped the door with the point of a penknife than 
it was drawn slowly downwards with a movement 
which reminded me of the tightening of a limpet on 
a sea rock, so that the crown which at first projected 
a little way above, finally lay a little below the sur- 
face o-f the soil. I then contrived to raise the door 
very gradually, despite the strenuous eftbrts of the 
occupant, till at length I was just able to see into 
the nest, and to distinguish the Spider holding on to 
the door with all her might, lying back downwards 
with her fangs and all her claws driven into the silk 
lining of the under surface of the door. 'I'he body of 
the Spider was placed across, and filled up the tube, 
the head being away from the hinge, and she obtain- 
ed an additional purchase in this way by blocking up 
the entrance.” 
Some .specimens of Trap-door Sjiiders, with their 
nests, from Mentone, France, are in the American 
Museum, New York. The nests show the curious 
sto})per-shaped traps, which, in common with the sur- 
rounding soil, are covered with a thick growth of 
mosses. 'I'he traps are exactly circular, and fit so 
closely tlnit they look as if they had been cut out of 
the earth with a sharp punch. A common form of 
the Mentone nest has a branch, or second tube, which 
joins the main at an angle of about forty-five degrees. 
'I’he branch sometimes reaches the surface, but is usual- 
ly a cid de sac. Every part of the work of these crea- 
tures challenges our admiration and astonishes us with 
that which so resembles the operation of mind. In 
the construction of this second tube there is a won- 
deiful exhibition of design. 'I'he opening into the 
second tube is closed by a trap door similar to the 
outer one, and it is hinged to the sharp angle which 
is formed by the union of the tubes ; the door is then 
used to fit either tube; it either closes the creature 
in the cul desac or in the lower portion of the main 
at his will. 'I'he uses of this second tube are not 
quite clear. It is noticed that the young build in 
the same manner, some nests being so small that a 
wheat-straw will fill them. 'I’he ingenuity of the 
Spiders is sometimes at fault. Glenerally the lichens 
remain quite green upon the surface of the cork trap- 
covers, but in some instances the latter become dry 
and the vegetation dies; this is readily seen, but the 
creature tries to remedy it by introducing bits of 
leaves, even freshly-cut leaves (usually dried ones), 
and bits of sticks, straw, etc. 'This is almost parallel 
with the example of an Aphrodite-worm which we 
have often seen building its tube in the warm waters 
of the Florida Reef. 'The latter creature selected 
from the surrounding debris, after excavating a tun- 
nel in the mud of the shallow lagoon, certa.in calcare- 
ous fronds of Algae, which like so many little bricks it 
laid in regular manner one upon the other, until a 
well had been built to the surface. In the work, at 
various points, fragments of sea-moss were introduced 
to hide its regularity, several inches of the tube being 
built above the surface. We wonder how it is that 
so low an organization as this simple Worm can se- 
lect from a mass of refuse matter on the sea bottom 
this one kind of material, and make use of it as ac- 
curately, and in the same manner, as a stone-mason 
builds his “ faced-wall.” In this instance the little 
plates of lime, which have lost their vegetable cover- 
ing by decomposition, are laid evenly upon each 
other, the whole tube presenting perfectly smooth 
and regular walls on the inside, which is also further 
finished as a mason plasters, by filling the joints 
with a kind of cement. 
Mr. Moggridge says : “ 'I’he nests are enlarged as the 
growth of the Spider requires ; the young constructing 
just as j)erfect ones as the old. I cannot help think- 
ing that these very small nests, built as they are by 
very minute Spiders, probably not very long hatched 
from the egg, must rank among the most marvellous 
structures of the kind with which we are acquainted. 
'I'hat so young and weak a creature should be able to 
excavate a tube in the earth many times its own 
length, and know how to make a perfect miniature of 
the nest of its parents, seems to be a fact which has 
scarcely a parallel in nature.” 'These large Spiders 
