164 NATURAL HISTORY. 



they lead a concealed life, making their way into any confined spaces in search of food and shelter. 

 One of the best-known species, the so-called Book Scorpion (Chelifer cancroides), is very common in old 

 houses, where it often lives in and among old dusty books and portfolios, whence its popular name. 

 It is about an eighth of an inch long. Several allied species (Chelifer nmscorum, <fcc.) are found 

 chiefly in moss, while others may be met with in hot-beds and among decaying vegetable matters, 

 upon the ground under herbage, and under the loose bark of trees. They run freely in all directions, 

 and when alarmed hold up their little pincers in a threatening manner. Their food consists of the 

 minute insects, mites, &c., which they meet with in the various places haunted by them ; and the 

 females are oviparous, usually producing about twenty eggs. The common house species, and probably 

 some of the others, have the curious habit of attaching themselves by their pincers to the legs of flies, 

 which may occasionally be found flying about thus loaded. Their object in this manoeuvre does not 

 seem to be understood. 



FAMILY IV. PHALANGIID.E. 



The Phalangiidae, or Harvest-men as they are often called, constitute a second family of 

 tracheate Arachnida, and some members of this must bs tolerably familiar to most of our readers. 

 They have a short, thick body, with an unsegmented cephalothorax, to which the abdomen, usually 

 composed of six distinct segments, is attached by the whole width of its base ; the chelicerae are three- 

 jointed and terminated by pincers, as in the Scorpions ; the first maxillary palpi are of moderate 

 length, and terminated by a simple claw ; while the second pair, and the three pairs of legs, are 

 usually of great length and slenderness, so that the creatures walk along as if mounted upon 

 stilts. In some exotic species, however, the legs, or some of them, are shorter and stouter, and 

 curved or furnished with processes which add to their grotesque appearance. The tarsi consist 

 of numerous joints, and are sometimes exceedingly long and slender. The cephalothorax bears 

 two ocelli. Respiration in these animals is effected solely by tracheae, which open by a single 

 pair of stigmata, each furnished with a valve, situated between the coxae of the last pair of legs 

 and the base of the abdomen. The Phalangiidae are oviparous, and the reproductive aperture is 

 situated quite at the base of the abdomen between the coxae, and from it the female can protrude 

 a long ovipositor. 



The Phalangiidae are numerous in species, and generally distributed over the earth's surface, 

 although their metropolis would appear to be South America, where also they display the most 

 remarkable forms. The species of temperate climates, and many of those of the tropics, have the legs 

 exceedingly long and slender, and similar in their development, like the species so common in our 

 gardens and fields. The best-known of these (Pluilangium opilio) is rather less than a quarter of an 

 inch long, of an ashy or yellowish grey colour, paler below. The female has a blackish band on the 

 back, and the male an erect horn on the chelicerae ; the cephalothorax, coxae, and femora are finely 

 spined. This species may be found almost everywhere, but especially on walls and the trunks of 

 trees, and although it frequently lurks in dark corners, obscurity does not seem to be so much an 

 object with it as with many other Arachnida. Still its greatest activity is in the evening, when it 

 wanders about in search of small insects, mites, and spiders, which it captures by a sudden rush. 

 According to some observers, these animals take more than a year to arrive at their maturity. 



The abdomen is always of comparatively small size in these animals, but in many of the South 

 American species of GonyJeptes and allied genera this part is still further reduced and almost com- 

 pletely concealed under the cephalothorax. which at the same time attains a somewhat increased size. 

 This peculiarity, coupled with a remarkable development of the hind legs, renders these South 

 American forms peculiarly grotesque. The posterior coxae are enormously developed, so that the 

 limbs of which they form a part seem to spring from points entirely behind the posterior end of the 

 body, and the component parts of the legs, which are generally a good deal thicker than their fellows, 

 are curved into various forms, and generally armed with spines and processes of different kinds. 



FAMILY V. SOLPUGID^. 



The Harvest Spiders of the last family are considerably more spider-like than the members of 

 any of the three preceding ones, and in those of this fifth family we have to do with creatures which 

 any one would denominate " Spiders," although they present, at all events, one character which 



