ORDER PULMONARY. 
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, Lctir ., 
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 
