INTRODUCTION. 
9 
arachnologists; this is the more extraordinary as the number, disposition, and relative size of 
the organs of vision constitute important elements in the classification of the Araneulea / 
Under the guidance of their respective instincts, a high degree of skill and industry is 
displayed by spiders in the construction of their retreats. Many species occupy holes formed 
by themselves beneath the surface of the earth, some of which, of a cylindrical shape, are 
lined with a compact tissue of silk, and have the entrance closed by a valve provided with a 
hinge, which can be opened and shut at pleasure. Other species fabricate in the crevices of 
walls, the crannies of rocks, beneath stones, on the leaves of vegetables, and under the ex¬ 
foliating bark of trees, tubes, cells, or domes of silk, on whose exterior surface soil, minute 
pebbles, and other heterogeneous materials are frequently distributed. Theridion riparium 
fabricates a slender, conical tube of silk, of a very slight texture, measuring from one and a 
half to tw r o and a half inches in length, and about half an inch in diameter at its lower extremity. 
It is closed above, open below, thickly covered externally with bits of indurated earth, small 
stones, and withered leaves and flowers, which are incorporated with it, and is suspended 
perpendicularly, by lines attached to its sides and apex, in the irregular stiare constructed by 
this species. In the upper part of this singular domicile the female spins several globular 
cocoons of yellowish-white silk, of a slight texture, whose mean diameter is about one eighth 
of an inch, in each of which she deposits from twenty to sixty small, spherical eggs, of a pale, 
yellowish-white colour, not agglutinated together. The young remain with the mother for a 
long period after quitting the cocoons, and are provided by her with food, which consists 
chiefly of ants. 1 2 3 
Various spiders run fearlessly on the surface of water, and some even descend into it; 
spontaneously, the time during which they can respire, when immersed, depending upon the 
quantity of air confined by the circumambient liquid among the hairs with which they are 
clothed. In this manner Argyroneta aquatica is enabled to pursue its prey, to construct its 
dome-shaped dwelling, and to live habitually in that liquid. There are, however, a few species 
of small size, Neriene longipalpis and Savignia. frontata , for example, which, though they do 
not enter water voluntarily, can support life in it for many days, and that without the external 
supply of air so essential to the existence of Argyroneta aquatica under similar circumstances. 8 
It is probable that this property may contribute to their preservation through the winter, 
when their hybernacula are liable to be inundated. 
For the purpose of securing their prey, spiders have recourse to divers expedients. 
Numerous species run rapidly about in quest of those objects which constitute their food ; 
others, approaching their victims with great circumspection, spring upon them from a distance; 
some lie concealed in flowers, or among leaves, seizing such insects as come within their reach; 
and many species procure a supply of nutriment by means of complicated snares of their own 
fabrication. Glossy lines intersecting each other at various angles, and in different planes, 
disposed, apparently, without any regular plan, compose one kind of snare. Another consists 
of a thin, horizontal sheet of web, having in connexion with it above, and in some instances 
also below, a number of slender lines arranged as in the preceding snare. A third kind is 
1 Ibid., vol. xi, pp. 165-167. 
2 ‘ Researches in Zoology/ p. 356. 
3 ‘ Report of the Third Meeting of the British Association for the Advancement of Science/ p. 446. 
