45G 



\RACHNIDA. 



were not known in Italy, we consider with MoufFet that the Lycosje, and other large Spiders which 

 do not construct webs, as well as the Solpugae, are the animals collectively known under the former 

 name and of which several species were described by the ancients. Lister, who first studied the 

 Spiders which inhabit Great Britain with great care, laid the base of a natural distribution, of which 

 those more recently published are mostly only modifications ; our more recent acquaintance with some 

 species peculiar to warmer chmates, such as as the Mason Spider, described by Sauvages, and other 

 analogous species, the employment of the organs of the mouth, introduced by Fabricius, a more pre- 

 cise study of the eyes and their relative sizes, and the relative length of the legs, have contributed to 

 perfect their arrangement. M. Walckenaer has entered into very minute details relative to these 

 animals, so that it is diflicult to detect a species which will not enter into the groups which he has 

 proposed. The presence or absence of a third unguis at the extremity of the tarsi affords another cha- 

 racter not yet sufficiently generalized, of which, however, Savigny has given a slight sketch (see 

 Walckenaer, Faun. Franf., note at the end of the genus Attus). 



M. L. Dufour, who has published excellent memoirs upon the anatomy of these insects, and 

 especially studied those of the kingdom of Valencia, where he has discovered many new species, has 

 paid particular attention to the respiratory organs of the Arachnida, and it is after his remark that we 

 divide them into those which have four pulmonary sacs, with four external spiracles, two on each side 

 close together, and those which have only two.* 



The first of these groups, which includes the Araneides theraphoses of Walckenaer, and some genera, 

 for which he has employed the collective name of Aranea, compose, in our method, the single genus — 



Mygale. 



The eyes are always situated at the anterior extremity of the thorax, generally close together. The 

 chelicera; and legs are robust. The majority have only four spinneretsf; the two lateral ones are situ- 

 ated rather above the two others, and are longer and 3-jointed, not computing the elevation which 

 forms their footstalk. They form silken tubes for their abode, which they hide either in the earth 

 into which they have burrowed, or under stones, in the bark of trees, or amongst the leaves. 



The Theraphoses of Walckenaer form a first division, characterized by four spinnerets, the two inter- 

 mediate and inferior generally very short, and the two exterior much exserted ; the hooks of the 

 chelicerie folded beneath, along the under side, and not along the inner surfaces. Eight eyes in all, 

 generally aiTanged upon a small eminence, three on each side, forming a reversed triangle, of which 

 the two upper ones are close together ; the two others in a line between the preceding. The fourth 

 pair of legs and then the first pair are the longest, the third the shortest. 



Those species which have the palpi inserted at the superior extremity of the maxillae so that they appear to be 

 six-jointed, the basal joint being long and narrow, and acting as the njaxilla; the tongue, always small, 

 and nearly square, and the two fore tibia; of the males with a strong spine beneath at the tip, form the restricted 



Mt/gale, Walck.,— some of which have not a transverse series of moveable, corneous spines at the upper 

 extremity of the chelicerse, above the place of insertion of the terminal hook. The hair on the under-side of 

 their tarsi forms a thick cushion, generally hiding the ungues. These are the largest species of the family, soiue 



* [The arrangement of the Spiders given by M. W;ilclienaer, in his last work, above 

 by Latreilie. The following is an abstract of his tabular synopsis :— 



eferred to, differs in some respeets from that employed 



Theraphoses .■} Eight eyes 

 '~' L eyes . 



" 1 Eiyht . 



Mygal. 



Genera. 

 , Filistata, I 



[Mr M'Leay, 



f Eyes near together . . .nygaie, riiisiaia, au. • l-Lateb 



■\Kyes apart Missulena / 



J Eves frontal Dysdcra, &c Tubici 



■ I Eyes frontal and laternl. Uptiotes, &c Cellul; 



^Eycs frontal and lateral, I Lyeosa, Dolophones, &c. Courei 



unequal /Eresus, Atlus, &c. . . . Voltigeuses 



,Thomisus, Sparassus, &e. Marchtuses 



Clubiona, &c Niditeles . 



J Pholcus, &c Filiteles . 



., ... 1 • J Teffenaria (Aranea), &c. Tapileles . 



Eyes frontal, equal-sued^ Epeira, &c. ..... Orbiteles . 



Linyphia Napiteles . 



ArKUS, &c Retitelcs . 



'-Argyroueta Aquiteles . 



I article upon some new forms of Arachnida, published in the Annals of Nutu 



Vagabonde 



Sedentaires . 



Aquatiques.] 



general cliaracter given of these groups, figuring one spec 

 three distinct segments, and one pair of the eyes < 

 articulated (Myrmarachne meUmocephala) ; and ; 

 instead of seven joints {Otiothops IValchenaeti).] 



t I have observed in Atypus the vestiges of two other nipple 

 the tour exterior ones, and are very visible ; but as they are lit 



th only two eyes (^Nops Ouanab 

 ly large [Dciiiupis Lamia) ; another with the head, thorax, and abd( 

 ■ith the fore-legs modified, in structure short, thickened, and compi 



/ History, has thrown doubts upon the 

 another, with the sternum divided into 

 en apparently 

 d of only six 



eing those which in the Spide 

 scarcely apparent, I have not 



I of the following divisijii are placed be 

 ounted them as such. 



