xv EPEIRIDAE 407 
which spin circular or wheel-like snares, the highest form of 
spider industry, together with a few forms so closely allied in 
structure to orb-weaving species as to be systematically insepar- 
able from them. It is practically co-extensive with the Argio- 
pinee, Tetragnathinae, and Nephilinae of Simon’s Argiopidae in 
the Histoire naturelle des araignées.' 
No one is unfamiliar with the orbicular snares, the structure 
of which has already been described with some minuteness (see 
p- 244), and some of the spiders which construct them are 
among the best known members of the order. 
It is impossible here to deal with the multitudinous forms 
embraced by this family. We must mention those genera richest 
in species, and some others of special interest. It will be con- 
venient to indicate eight sub-faimilies or groups, which include 
most of the forms likely to be met with. These are the THE- 
LIDIOSOMATINAE, TETRAGNATHINAE, ARGIOPINAE, NEPHILINAE, 
EPEIRINAE, GASTERACANTHINAE, POLTYINAE, and ARCYINAE. 
G.) The THERIDIOSOMATINAE are a small group which might 
with equal propriety be classed with the Theridiidae or the 
Epeiridae. Zheridiosoma argenteolum is a rare spider in Dorset- 
shire. It is a minute spider, one-twelfth of an inch in length, 
with silvery white globular abdomen variegated with reddish 
brown, and yellow cephalothorax with darker caput. Some 
allied spiders spin a roughly circular snare. 
Qi.) The TETRAGNATHINAE consist chiefly of two genera, Pachy- 
gnatha and Tetragnatha. The first consists of spiders which are 
not orb-weavers, but live in herbage, especially in swampy places. 
Two species, Pachygnatha clerckit and P. degeerii, are common in 
England, and a third, P. listeri, is sometimes met with. They 
are rather striking, prettily marked spiders, with strongly 
developed chelicerae. 
The species of 7etragnatha are true orb-weavers, and may easily 
be recognised by their cylindrical bodies, elongated chelicerae, and 
long legs, stretched fore and aft along the rays of their webs. Five 
species have been recorded from England, and the genus contains 
at least a hundred species in all; almost every country in the 
world, regardless of its latitude, supplying examples. 
1 T.e, as developed in the course of the work, not as set forth on p. 594 of vol. 
i., where five sub-families are established (Theridiosomatinae, Arciinae, Eurycor- 
minae, Amazulinae, Poltyinae), which are afterwards merged in the Argiopinae. 
