contact, and viscid matter is emitted from the papillae; they are then separated by a lateral
motion, which extends the viscid matter into fine filaments connecting the papillae ; on these
filaments the current impinges, drawing them out to a length which is regulated by the will of
the.animal, and on the mammulae being again brought together, the filaments coalesce and
form a compound line.
Many intelligent naturalists entertain the opinion that spiders can forcibly propel or dart
out lines from the spinners; but when placed, on twigs set upright in glass vessels with perpendicular
sides, containing a quantity of water sufficient to immerse their bases completely,
all the efforts they make to effect an escape uniformly prove unavailing in a still atmosphere.
However, should the individuals thus insulated be exposed to a current of air, either naturally
or artificially produced, they immediately turn the abdomen in the direction of the breeze, and
emit from the spinners a little of their viscid secretion, whioh being carried out in a line by
the current becomes connected with some object in the vicinity, and affords them the means
of regaining their liberty. If due precaution be used in conducting this experiment, it plainly
demonstrates that spiders are utterly incapable of darting lines from their spinners, as they
cannot possibly escape from their confinement on the twigs in situations where the air is
undisturbed, but in the agitated atmosphere of an inhabited room they accomplish their object
without difficulty. Similar means are frequently employed by spiders in their natural haunts
for the purposes of changing their situation and fixing the foundations of their snares.
The webs named gossamer are composed of lines spun by spiders, which, on being
brought into contact by the mechanical action of gentle airs, adhere together, till by continual
additions they are accumulated into irregular white flakes and masses of considerable magnitude.
Occasionally spiders may be found on gossamer webs after an ascending current of rarefied
air has separated them from the objects to which they were attached, and has raised them
into the atmosphere ; but as they never make use of them intentionally in the performance of
their aeronautic expeditions, it must always be regarded as a fortuitous circumstance.1
M. Bon, a Frenchman, and M. Tremeyer, a Spaniard, have succeeded in fabricating
stockings, gloves, purses and other articles, of the silk produced by spiders; but the great
voracity of these animals, and the difficulty experienced in providing them with food, have
hitherto prevented this material from being made available for manufacturing purposes on an
extensive scale.
1 I Transactions of the Linnean Society/ vol. xv, pp. 449-459. * Researches in Zoology/ pp.
229-252.
S P I DE RS
OF
GREAT BRITAIN AND IRELAND.
Class ARACHNIDA. Order ARANEIDEA.
Tribe OCTONOCULINA.
Family MYGALIDiE.
The Mygalidm, whioh abound most in hot climates and comprise the largest spiders known,
have the falces articulated horizontally; two branchial and two tracheal opercula, situated near
the anterior extremity of the abdomen, on its under side, are conspicuous in most species, but
in some the branchial opercula only are apparent; much the greater number are provided with
two pairs of spinners, and have the inferior surface of their biungulate tarsi, and of the digital
joint of their pediform palpi, in the females, densely clothed with compound, hair-like papillae,
constituting an apparatus which, by the emission of a viscous secretion, enables them to
traverse the perpendicular surfaces of dry, highly polished bodies; others have three pairs of
spinners, are destitute of hair-like papillae on the legs and palpi, and have the tarsi terminated
by three claws.
The spiders belonging to this extensive family conceal themselves in holes in the earth,
in hollow trees, or among the leaves of plants, and prey upon large insects, which they
actively pursue or take by surprise; hitherto, only one species has been found m Great
Britain.