THE 



171 



of silk ; but instead of closing its aperture with a trap-door, the nest is finished by continuing the 

 lining-tube beyond its mouth for a greater or less distance, the part thus left free lying upon the 

 surface of the ground. The female deposits her eggs, which number from thirty to forty, in a silken 

 cocoon, which she attaches to the inner extremity of her nest. 



TRIBE II. DIPNEUMONES. 



The Dipneumones, as indicated by their name, possess only a single pair of lung-sacs, and the 

 base of the under surface of the abdomen shows only a single pair of the opercula closing their 

 apertures. The tracheal system has its apertures either immediately behind those of the lung-sacs or 

 near the end of the abdomen. These Spiders, however, have another distinctive character in their 

 falces, which may be placed either vertically or in an inclined plane, but always have the claw-joints 

 articulated so that they bend in towards the middle line of the body. 



FAMILY II. SALTICID^, OR SALTIGRAD^E. 



The first two families of this tribe have the eyes nearly always placed in three transverse rows 

 upon the surface of the cephalothorax. That is to say, we may distinguish two rows of two each and 

 a third containing four, although in many cases an imaginary line may be recognised as combining the 

 two separated pairs into a single curved row. In the Salticidae the general form is compact, and the 

 cephalothorax of nearly equal width from back to front, so that its shape is more or less rectangular. 

 The legs are comparatively short and stout, and usually terminated by a pair of claws, below which 

 there is a bunch of hair-like papillae, termed a scopula, although sometimes this organ is wanting, and 

 there are three claws. The extremity of the abdomen has three pairs of spinnerets. 



The Salticidse are generally neat and active-looking Spiders, of small or moderate size. The 

 species are exceedingly numerous, and distributed in all parts of the world. Those of warm climates 

 include the largest forms, and many of them display a remarkable brilliancy or iridescence of 

 colouring. They are of wandering habits, preparing no snares for the capture of the flies and other 

 insects on which they feed, but prowling about in search of their prey with a most extraordinary cat- 

 like stealthiness, and often capturing it by means of a sudden spring. Their habit of making little 

 jumps under such circumstances, and even when merely alarmed, has caused the family to receive the 

 name of Saltigradse, and is also alluded to in the name of the 

 typical genus Salticv.-s, upon which the family name Salticidse is 

 founded. They are to be found upon the trunks and leaves of 

 trees and bushes, on railings, and about rocks and walls, in 

 fact, wherever the flies which constitute their principal nourish- 

 ment are to be met with. At the approach of danger they take 

 shelter in holes and crevices, or throw themselves off and drop 

 to the ground at the extremity of a fine silk thread, which 

 it will be found they drag behind them, and attach from point 

 to point all the while they are engaged in their predatory wan- 

 derings. This habit may be easily observed during the summer 

 in the case of the commonest of the British species (Salticus 

 scenicus), which may be met with almost everywhere in abun- 

 dance, running about in the hot sunshine upon brick walls, 

 palings, and the trunks of trees, and even upon the iron railings 

 of balconies and other parts of houses in London itself. This 

 interesting little creature, which is about a quarter of an inch 

 long, and black, with white interrupted transverse bands, has a singularly alert look when engaged 

 in its search for prey. Nevertheless, it moves everywhere with the greatest circumspection, and 

 occasionally, by straightening the fore legs, elevates the front of the cephalothorax, in which we find 

 a pair of enormous eyes, so as to obtain a wider range of vision. Its progress upon smooth and 

 perpendicular surfaces is facilitated by the scopulae, or tufts of adhesive hair-like papillse placed at 

 the extremity of each foot ; and when by this cautious method of approach the Spider has arrived near 

 enough to its intended victim, by a sudden rush and spring the latter is at once seized and soon 

 destroyed. Upon thin iron railings we have seen this Spider advance along the lower surface of the 



SALTICUS SCENICUS. 



A, female, enlarged; B, foot from below with scopula ! 

 c, foot from the side ; D, falces of male. 



