P R E F A C E .
When exceedingly minute spiders are made the subjects of investigation, it is essential that
the sexual organs should be closely inspected, as they afford, by their complete development, an
-infallible criterion that the animals have arrived at maturity; they also present, by their greatly
diversified organization? particularly as regards the males, in which sex they are connected with
the digital or terminal joint of the palpi, excellent specific characters, the value of which will be
duly appreciated when it is recollected that many species so nearly resemble each other in size
and colour as to be distinguished by differences in structure only.
The difference in the number of eyes with which spiders are provided, supplying, as it does,
well-marked characters not difficult to be ascertained, has been taken as the most convenient and
satisfactory basis of their distribution into tribes. On this principle the three following tribes
have been founded, which include all the species hitherto discovered:
1. Octonoculina; eyes eight.
2. Senoculina; eyes six.
3. Binoculina ; eyes two.
The first tribe, Octonoculina, is much the most extensive of the three, comprising numerous
genera, which exhibit considerable differences in organization and economy; the second tribe,
Senoculina, includes ten or eleven genera, species belonging to many of which are found in this
kingdom; and the third tribe, Binoeulina, contains the single genus Nops, instituted by Mr. W.
S. MacLeay for the reception of two remarkable species of extra-European spiders. It may be
further remarked, that to the families previously established another has been added, namely,
the Cinifonidee; and that several new genera have been introduced, whose characters are defined
in their appropriate places.*
In preparing the following pages for publication, the principal authorities consulted were
Lister, Latreille, Walckenaer, Sundevall, Hahn, Koch, Wider, Duges, Audouin, Owen, &c.,
from whose writings much valuable information has been derived.
It remains to acknowledge the kind assistance of friends from whom specimens have been
received; but as the obligations to each will be expressed as suitable occasions present
themselves, it is not requisite to allude to them more particularly in this place.
INTRODUCTION.
LlNNiEUS and the naturalists of his school have included spiders in the extensive class
Insecta, having constituted with them the genus Aranea, comprised in the order Aptera.
Subsequently, zoologists have removed the Aranete and several nearly allied groups from the
apterous insects, and have established with them the class Arachnida. Of this class the
spiders form the order Araneidea, which is divided into tribes, families, and genera. A concise
summary of the more important facts relating to the organization and economy of these
animals, which have been disclosed by the researches of anatomists and physiologists, will
herve to elucidate the history of species.
Spiders, with few exceptions, have a cephalo-thorax, or the head continuous with the
chest; but the cephalic may readily be distinguished from the thoracic portion by the presence
of the eyes, which are two, six, or eight in number; by the falces,1 situated in front, and
terminated by a pointed fang which has a ginglymoid movement; and by the oral apparatus
connected with its, inferior surface. The parts of the mouth consist of two maxillae, each
provided with a palpus of five joints, having between them a sternal labium, and above them
a palate to whose superior surface a small labrum is attached. Bight legs, of seven joints
each, having two or more claws at their extremity, are articulated round the cephalo-thorax,
to the posterior part of which the abdomen is united by a short, cartilaginous pedicle. The
abdomen is moveable, without division, terminated by a small, angular process, which covers
the anal orifice, and by four, six, or eight fleshy mammulae, placed directly below the anus,
from which the silk proceeds in the act of spinning. On the under side of the abdomen, near
its anterior extremity, there are two or four respiratory apertures or stigmata; and in the
middle of the space which separates them the external foramen of the sexual organs is situated
in the females, but in the males these organs are connected with the terminal joint of the
palpi; consequently, they are double.
The cephalo-thorax is covered on the upper .part with a plate, which is generally
Coriaceous, but in some instances is hard and corneous. It varies considerably in figure, the
1 The term falces is applied to the organs improperly denominated mandibles, which, being
^'situated above the labrum, form no part of the oral apparatus. See the - Transactions of the Linnean
Society,’ vol.jxxi, p. 37. c