16 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
afield, upon the ground, water, or trees, and as a rule have no fixed domi- 
cile, except at the brooding time and during winter. These principal groups 
are subdivided into seven secondary groups, sections or suborders.! 
ae The four tribes comprising the Sedentary spiders are named strictly 
ary ss . eee aCe nse . . ae an ; Bic 
Grows. from the chief characteristics of their spinningwork, viz.: the Orbi- 
telarie, from their orb shaped web; the Retitelarie, from their 
net like web or snare of crossed lines; the Tubitelarie, from the tubular 
web which they spin, and from the opening of which, in some species, a 
close textured snare spreads out in 
all directions; the Territelarie, from 
the silken cylinder with which the 
typical species line their burrows 
in the ground. 
The Wandering spiders include . 
three tribes, which are conspicuous 
by their ordinary independence of 
snares for the capture of prey, and 
have been named from certain pe- 
culiarities of motion. The 
Laterigrade haye legs so 
inserted as to permit a 
motion sidewise, as well as forward 
or backward. For this reason La- 
treille called them also Crab spiders. 
The Citigrade include those species 
that keep chiefly to the land and 
water, upon which they run with 
great rapidity. The Saltigrade, or 
vaulting spiders, are named from 
their hopping moyement in ordi- 
nary progress. The individuals of 
these three tribes are almost equal- 
ly entitled to be called citigrades, 
for they all move swiftly, but the 
Citigrades technically so termed are 
Fic. 2. Territelarie : Burypelma Steindachnerii Ausserer. habitually running spiders, keeping 
a cas a ca ni closely upon the ground, while the 
Laterigrades and Saltigrades are arboreal, habitually dwelling upon plants 
and vertical surfaces. The three are also quite distinct in their structure, 
and the systematic position of any one, as far as above indicated, can com- 
monly be told by a glance at the form. 
W ander- 
ing Group 
1 Thorell uses the term “suborders” in his European Spiders for these principal groups, 
but adopts the term “sections” in his “Descriptions of the Aranez of Colorado” (Bulletin 
U.S. Geological Survey, Vol. III., No. 2, page 477, note), and still later the name tribe (tribus). 
