298 



ARACHNIDES. 



ULOBORUS, Lat. 



The four posterior eyes placed at equal intervals on a straight line, 

 and the two lateral ones of the first line nearer to the anterior edge 

 of the thorax than the two comprised between them, so that the line 

 is arcuated posteriorly. Their jaws, like those of the Epeirae, begin 

 to widen a little above their base, and terminate in the form of a 

 palette or spatula. The tarsi of the three last pairs of legs terminate 

 by one small nail. The first joint of the two posterior ones has a 

 range of small setse. 



The body of these animals, as well as in the following subgenus, 

 is elongated and nearly cylindrical. Placed in the centre of their 

 web, they advance their four anterior legs in a straight line, and 

 extend the two last in an opposite direction ; those of the third pair 

 project laterally. 



These Arachnides construct webs similar to those of other Orbi- 

 telae, but they are looser and more horizontal. They will completely 

 envelope the body of a small coleopterous insect in less than three 

 minutes. Their cocoon is narrow, elongated, angular at the margin, 

 and suspended vertically to a web by one of its extremities. The other 

 end is bifurcated or terminated by two prolonged angles, one of 

 which is shorter than the other, and obtuse; there are two acute 

 angles on each side. For these interesting observations I am indebted 

 to my friend M. Leon Dufour. 



Uloborus Walckenaerius, Lat*. About five lines in length ; 

 reddish-yellowish ; covered with a silky down forming two series 

 of little fasciculi on the top of the abdomen; paler rings on the 

 legs. From the woods in the vicinity of Bourdeaux. and in 

 various departments of the south of France. 



TETRAGNATHA, Lat. 



The eyes placed 'four by four on two nearly parallel lines, and 

 separated by almost equal intervals; jaws long, narrow, and only 

 widened at their superior extremity. The chelicerae are also very 

 long, in the males especially. The web is vertical f. 



EPEIRA, Walck. 



The two eyes on each side approximated by pairs, and almost con- 

 tiguous ; the remaining four forming a quadrilateral in the middle. 

 The jaws dilate from their base, and form a rounded palette. 



The cucurbitina is the only species known whose web is horizon- 

 tal ; that of the others is vertical, or sometimes oblique. 



Some place themselves in its centre in a reversed position, or with 

 their head downwards ; others construct a domicil close by it, either 

 vaulted on all sides, or forming a silky tube composed of leaves 

 drawn together by threads, or open above, and resembling a cup or 

 the nest of a bird. The web of some exotic species is formed of such 



* Lat., Gen. Crust, et Insect., I, 109; see also second edition of the Nouv. 

 Diet. d'Hist. Nat., article Ulobore. 



t Tetraynatha exlensu, Walck., Hist, des Aran., V, vi ; Aranea exlensa, L., Fab., 

 De Geer ; Aranea viresccns ? Fab. ; Aranea, maxillosu, Id. See Tab. des Arun. of 

 Walckenaer. 



