CHAPTER ]X. 

 HORIZONTAL SNARES AND DOMED ORBS. 



Tiiic Orbwobs heretofore considered all belong to the general division 



described as vertical orbwebs. The snares to be considered in tliis eliaiiter 



are known as horizontal orbs. The horizontal orbweb in all es- 



^°r*°'y'^sential particulars is woven like the vertical orb and differs chielly 



berosa ^" ^^^^ ^'^'^^ *^'''^ ^* ^^ usually hung wholly or partly in a 

 horizontal jiosition. 

 In the s])ecies making vertical webs, the habit is so tirndy iixed that 

 the spiders rarely deviate therefrom, and never, except under circumstances 

 which constrain a departure. Nevertheless, it is interesting to remark that 

 sometimes they do spin orbs that more or less approximate the horizontal. 

 Occasionally these orbs are entirely horizontal. For example, I have 

 known a brood of young Epeira sclopetaria, freshly escaped from tlie co- 

 coon, to spin u})on the same object minute orbs, some of which were ver- 

 tical, while others were as truly horizontal as though they had been made 

 Ijy a species that haliitually weaves an orb of that sdil. Fig. 141. It was 

 not diflicult for me to determine that these individuals were inHuenced to 

 an abnormal act by the conditions under which they wrought. It was 

 comparatively easy for them to get foundation lines so placed that a hori- 

 zontal web almost inevitabh' resulted ; while, on the other iiand, 

 Vana- i\^q frames for a vertical web could not have been obtained 

 th'^n^ except with the greatest difficulty. Yet, in the case of a few of 

 Plane ^^^'^ same brood nearly as great difficulties were overcome, and a 

 vertical web was made. For examjile, tlie little fellows in the 

 cut (Fig. 141) found it easy to weave an orb horizontally around the metal 

 frame tliat supports the lamp fbimncy, :iiid this they ilid. lint otlu'i's fol- 

 lowed the specific habit and sent down lines to the table, making a 

 triangular frame and a vertical orb within it. 



So, too, it may be said that spiders which make hoiizontal snares arc 

 sometimes constrained by difficulties of the site chosen to deviate more or 

 less from the horizontal plane. Indeed, I have si'cn the orb of Tetrag- 

 natha inclmed at almost every angle, and occasionally have found it spun 

 in an absolutely vertical position. 



(150) 



