ORDER PULMOXARI^. 413 



the variety of colours of the abdomen, and the short duration 

 of their life ; but they make webs with a regular net-work, 

 composed of concentric circles, crossed by straight radii, 

 diverging from a centre, where these spiders always remain 

 in an inverted position, towards the circumference. Some 

 conceal themselves in a cavity, or a lodge which they have 

 constructed near the edges of the web, which is sometimes 

 horizontal, sometimes perpendicular. Their eggs are agglu- 

 tinated, very numerous, and enclosed in a voluminous cocoon. 

 The threads which support the web, and which may be 

 elongated to about one- fifth of their length, are used for the 

 divisions of the micrometer. This observation has been com- 

 municated to us by M. Arago. 



LiNYPHiA, Latr., 



Well characterized by the disposition of their eyes : four in 

 the middle, forming a trapezium, of which the posterior side 

 is wider, and occupied by two eyes, much thicker and more 

 apart, and the four others grouped by pairs, one on each side, 

 and in an oblique direction. Their jaws are widened only 

 at their superior extremity. 



They construct on bushes, brooms, &c. a horizontal, thin 

 web, of no great compactness, and spread above it, on several 

 points, or in a very irregular manner, other threads. This web 

 is thus a sort of mixture of those of the inequiteles and orbi- 

 teles. The animal remains at the lower part, and in an 

 inverted posture. 



Uloborus, Latr , 



Have the four posterior eyes placed at equal intervals on a 

 straight line, and the two lateral ones of the first line more 

 approximated to the anterior edge of the corslet than the two 

 comprized between them, so that this line is arched back- 

 wards. The jaws, like those of the epeira, begin to widen a 



