Fig. 52.—Foot of Garden Spider.
Fig. 53.—Spinnerets of Garden Spider.
Two other points remain to be noted. The feet should be examined, for their structure throws some light on the way in which the Garden Spider runs so securely to and fro on the radial lines. One of the legs of a dead specimen should be detached, and its armature of spines and hairs noted. The foot is armed with three stout claws, which are pectinated—that is, toothed like a comb, and beneath them are smaller ones, sometimes described as toothed hairs. It will be easy to understand what a secure foothold these claws give the animal as it runs backwards and forwards over the radial lines; for if the web be shaken by the wind or designedly its owner can take a firm hold with each foot, and thus have eight separate points of attachment. An inch hand lens is quite sufficient to give a general idea of the hairy and spinous clothing of the legs and the position of the claws; but to see the teeth a higher power—a half-inch—will be necessary.
It is a good plan to choose a freshly killed specimen for the examination of its spinnerets. If the spider is laid on its back in a glass dish, gentle pressure on the abdomen away from the cephalothorax will cause the material secreted by the spinning-glands to ooze out. This, however, cannot be done if the specimen has been for some time in spirit. We shall be able to make out six tubes (four of them larger than the other two) grouped round the anal aperture; but, for the present, we must take for granted the fact that these are made up of a number of smaller tubes, so that the end of each spinneret is not unlike the rose of a watering-can. A good half-inch will give some indications of this rose-like appearance.
The Jumping Spider (Sal´ticus sce´nicus) belongs to a family the members of which make no web or snare for the capture of prey, but trust for their food-supply to their skill in stalking flies and other insects, which they capture by a sudden spring. It is from this habit that the type-genus and the family have received their scientific and popular names.
The common British species is extremely abundant, and wherever flies are plentiful these spiders will not be very far off. This is the case not only in the country, but also in London and other large towns. It is a noticeable spider from its coloration—black marked with white. The eyes are eight in number; though the artist in our illustration has only represented four. The centre two of the front are the largest of all, and have been compared not inaptly to bull’s eyes. Two others are placed on each side of the cephalothorax, so that the eyes form, roughly, three sides of a square, and the central eyes in the lateral lines are the smallest. We may represent them thus
, while the eyes of the Garden Spider are disposed in this fashion