4b4 ARACHNIDA. 



much shorter than the thorax, and covered half way from the base by a solid epidermis. M. fulva, Brazil. There 

 also appear to be other species in Georgia, in North America. 



[Myrmarachne, MacLeay, appears only to be a geographical section of Myrmecia, having the head portion of the 

 cephalothorax more elongated, whereby the posterior eyes are removed wider apart. M. atra of Perty, is precisely 

 of the same form as Myrmarachne melanocephala. It is likely to lead to erroneous impressions to assert that 

 these Spiders prove that the order may include species with additional articulations, as they are only constricted 

 in several places, and not articulated.] 



The second section of the Wandering Spiders, that of Saltigrades, has the eyes arranged in a large 

 square, the front row extending the whole breadth of the thorax, which is nearly square, or semi-oval, 

 flat, or but slightly gibbose above, as broad in front as in any other part, and suddenly deflexed at the 

 sides. The legs are fitted for running and leaping ; the fore-thighs are often greatly dilated. 



One of these insects is very common in summer {Aranea scenica, Linn.) upon walls and windows 

 exposed to the sun, takes short leaps, stopping suddenly after a few steps, and raising itself on its legs. 

 When it discerns a fly, or especially a gnat, it approaches it cautiously till within leaping distance, 

 when it darts upon it, not fearing to take a perpendicular leap, because it always at the same time 

 suspends itself by a thread, which it winds off as it advances. It also serves to suspend it in the air, 

 and to mount up again to the spot whence it leaped, or to sustain it whilst the wind carries it from 

 place to place. Such are the general habits of this section. Many species construct, amongst the 

 leaves, under stones, &c, silken nests, in the form of oval sacs, open at each end, into which they 

 retire in order to take rest, to moult, and to take refuge against the inclemency of the weather. If 

 menaced with danger they quit their retreats, and run off with great agility. Some species construct, 

 with the same material, a kind of tent, which serves for the birth-place of their posterity, and in which 

 the young reside for some time with their parent. Other species, resembling Ants, elevate their fore- 

 legs and vibrate them with great rapidity. The males sometimes engage in contests, in which their 

 manoeuvres are very singular, but which do not terminate fatally. 



Tcssarops, Rafinesque, nearly approaches the next, but differs, if there be not some error, in the number of its 

 eyes, which is only four. (See Annal. Gen. Set. Physiq., torn, viii.) 



Palpi ma ii us, Dufour (in ditto, torn, v.), appears also intermediate between Eresus and Salticus, the eyes being 

 arranged as in the former ; the tongue is also triangular and pointed, and the maxilla? are dilated and rounded at 

 the tip, but they are inclined; the terminal joint of the anterior tarsi is inserted laterally, and wants the ungues. 

 P. gibbus, Dufour, does not leap, but only creeps slowly. It is found under stones in Valencia. M. Lefebvre 

 brought a new Spider from Sicily, which appears to belong to this genus. 



In the two following genera there are always eight eyes, and the maxillae are straight. 



Eresus, 'Walck., has four of the eyes arranged in a small square in front of the thorax, and the other four form- 

 ing a much larger square at its sides ; the tongue is triangular, and the tarsi terminated by three ungues. 

 E. cinnaberinus, Walck., Aranea i-guttata, Rossi, &c. 



Salticus, Latr., Alius, Walckenaer, has four of the eyes in across line in front of the thorax, the two middle ones 

 being the largest, and the two others at the sides of the thorax, thus forming a large square open behind ; the 

 tongue is very obtuse at the tip, and the tarsi have only two terminal ungues. The males of many species are 

 furnished with very large chelicerae. Some species have the thorax thick, sloping, and very much inclined at the 

 base. Aranea sanguinolenta, Linn., South of France, and many other species. 



The others have the thorax flattened and roof-like at the base, the body being rather oval, and clothed with thick 

 pubescence, with the legs robust, as in Aranea scenica, Linn., or narrow, elongated, subcylindrical, and naked, 

 with the legs long and slender, as Aranea forniicaria, De Geer. 



[Since the second edition of this work many additional genera of Spiders have been published by Mr. 

 Blackwall, in the London and Edinburgh Philosophical Magazine, from time to time, as well as by 

 M. Walkenaer, in the work above referred to. The genera Cherses, Arkys, Erigona, and Plectanus, 

 established by the latter, are extremely singular in their forms. The former of these authors has 

 devoted much attention to the economy and structural peculiarities of many species of Spiders, his 

 researches being published in the Transactions of the Linneean Society. M. Hahn also commenced 

 the publication of an elegant little work. Die Arachniden, since his death continued by M. Koch, in 

 which a vast number of Spiders are described and figured. M. Perty also described and figured many 

 Brazilian species in his Delectus of the Articulated Animals of Brazil. A great number of European 

 species are also figured by Herrick Schaffer, in his continuation of Panzer's work upon Germau 

 insects. M. Lucas, who is attached to the entomological department of the Jardin des Plantes, has 

 made these insects his particular study, and has communicated some interesting species to Guerin's 

 Magasin de Zoologie and the Annates de la Societe Entomologique de France. 



