HORIZONTAL SNARES AND DOMED ORBS. 



151 



Such are the facts in the case. Whether this accidental tendency on 

 both sides to vary the iiabitual position of the snare may have hiid 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, tlie diffi- 

 culties of originating a fixed habit from such an accidental 

 are so formidable that they seem practically insur- 



Develop 

 ment. 



variation 

 mountable. In ad- 

 dition to these is 

 the difficulty of ex- 

 plaining why the 

 same accidental va- 

 riation, appearing 

 with equal frequen- 

 cy in 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 ujion 

 horizontal snares 

 are Argyroepeira 

 hortorum, Epeira 

 gibberosa, and the 

 various species of 

 the genus Tetrag- 

 natha, and the sev- 

 eral species of Uloborus. For reasons which 

 wall hereafter be explained I do not include 

 the last named species w'ithin the group to 

 be described in this chapter. pj,; ^ 



Argyroepeira hortorum, or tlie Orchard 

 spider of Ilciitz,^ 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 tlie cold climate of New England 

 and the winterloss regions of the Soulli. Its web is usually found in low 



Varied orbs of a colony of 

 spiderlings. 



Orchard 

 Spider. 



^ Epeira hortonnn Ilontz, "Si)i(U'i-s u{ the United States;" Argyroepeira liurtorum 

 Emerton, " New Euglaud Epeiridaj," page 333. 



