= =e 
HORIZONTAL SNARES AND DOMED ORBS. 151 
Such are the facts in the case. Whether this accidental tendency on 
both sides to vary the habitual position of the snare may have laid the - 
foundation upon which has been developed the permanent habit which we 
are now to consider, is a point which others, perhaps, may be able to 
settle, to their own satisfaction at least. To my mind, the diffi- 
culties of originating a fixed habit from such an accidental 
variation are so formidable that they seem practically insur- 
mountable. In ad- 
dition to these is 
the difficulty of ex- 
plaining why the 
same accidental va- 
riation, appearing 
with equal frequen- 
cy im many species, 
should have  suc- 
ceeded in fixing it- 
self upon a few 
species alone ? 
In the United 
States the spiders 
which habitually 
are found upon 
horizontal * snares 
are Argyroepeire 
hortorum, Epeira 
gibberosa, and the 
various species of 
the genus 'Tetrag- 
natha, and the sey- 
eral species of Uloborus. For reasons which 
will hereafter be explained I do not include 
the last named species within the group to 
Develop- 
ment. 
be described in this chapter. Fig. 141. Varied orbs of a colony of 
Argyroepeira hortorum, or the Orchard spiderlings. 
spider of Hentz,’ is one of the most beautiful of our indigenous species, 
presenting in its varied green, yellow, and metallic silver colors 
all the characteristics of some of the brightest tropical species. 
It is widely distributed, probably throughout the entire United 
States, and is thus equally at home in the cold climate of New England 
and the winterless regions of the South. Its web is usually found in low 
Orchard 
Spider. 
‘Epeira hortorum Hentz, “Spiders of the United States;” Argyroepeira hortorum 
merton, “New England Epeiride,” page 333. 
