588 CLASS IX. 
Orper VIII. Aranerdea. 
Palps subfiliform, with last jomt in males supplied with various 
appendages, subservient to copulation. Abdomen covered with 
skin continuous, mostly soft, constricted at the base or joined to 
the cephalothorax by means of a petiole. Stigmata never more 
than four, mostly only two. Respiration in all pulmonary, in some 
tracheal at the same time. 
Family XV. <Araneidea (Aranee Later.) Characters of the 
order also those of the single family. 
(Mandibles monodactylous, with terminal claw perforate, for the 
excretion of a poisonous liquid. Jour or six papille cylindrical or 
conical at the inferior surface of abdomen, situated towards the 
posterior part, perforated by very minute foramina for the passage 
of a silky substance. Feet different in length, similar in form, 
terminated by a double or triple claw.) 
The spiders. All these animals prepare from a silky substance 
certain filaments with which they cover their eggs. Many, from 
the same substance, form also webs and nets in which they capture 
their prey. At the hind part of the body four, or in most species, 
six spinarets are found, beset with fine tubules through which the 
silky matter escapes. The secretion is effected in the form of an 
adhesive fluid by means of glands, or tubes of very different form, 
pear-shaped, glandular sacs united in groups, blind tubes convoluted 
and ramified. See Trevrranus Ueber den innern Bau der Arachnid. 
s. 41—44, Tab. Iv, v. figs. 42—44 ; Verm. Schr. 1. s. 11, 12, Tab. 1. 
fig. 4, H. Mecxen Arch. f. Anat. u. Physiol. 1846, s. 50—56, Taf. 
1. figs. 388—45. 
The long threads that cover the fields or float in the air, especially 
in the fall of the year, (Gossamer, Herfstdraden, fils de la Vierge, 
Herbstgarn, der fliegender Sommer) are considered by some writers 
to be products of the atmosphere, or exhalations from plants; the 
chemical investigation of G. J. Muuprer has proved that these 
threads agree in composition with silk, and beyond doubt are the 
work of spiders. 
See Natuur-en Scheikundig Archief, and a postscript by my hand, in 
which I have cited some works on this subject. LLATREILLE ascribes these 
