140 AMERICAN SPIDEUS AND THEIK Sl'INNINCiWdlUv'. 



Spirals wcri' tlius drawn in sliortri' loops uitli niucli less ciu'vc, ami the 



centre of the huh was well toward the toj), two inches therefrom. In an- 



otiier adult weh the orb measured eleven inches long by eight wide, tlie 



nvunlji'i' of I'adii was forty-one, of spirals forty-five, of notched concentrics 



nine. The centre of the hul) was five inches from the topmcst sjural. 



The following measurements give some idea of the size of Tri- 



^^^ aranea's orb: Web No. 1, about four inches diameter; radii 



. forty-three ; spirals thirty-five. No. 2, radii twenty ; spirals 



twenty. No. 3, diameter six and a half inches; radii thirty-five; 



spirals thirty-five. No. 4, seven inches long by six wide. No. T), six and 



a half long by five and a half wide. Radii forty ; si)irals, forty-eight 



below, twelve above. No. 6, forty-one radii ; forty-five spirals. No. 7, two 



and a half by two and a half. No. 8, eleven by eight inches, central five 



inches from to[), three and one-fourth from 

 side; radii forty-one, spirals fortj'-five, notched 

 zone nine. 



Triaranea is frequently found in the neigh- 

 borhood of human habitations, around barns 

 and various outbuildings of farms, but also 

 loves the field, and is frequently found therein. 

 It does not appear to have in so marked a de- 

 gree as Labyrinthea a preference for nest sites 

 naked of foliage, when such can be conven- 



Fi(^ 130. The looped spirals, L.S., in IPntly prOCUred. 



ziiia's orb. q'']^g mazc or snare of netted lines in the 



wi^l) of Triaranea is, on the whole, not quite so prominent as that of Lab- 

 yrinthea, but in some cases it is very lieavy, and generally is decidedly 

 marked in the adult spider. The variation in this portion of 

 .|^ the snare may be seen from the following extract from my note 

 book, made during one day : No. 1, retitelarian lines not heavy ; 

 No. 2, little or no retitelarian lines ; No. 3, slight retitelarian lines above ; 

 No. 4, retitelarian lines quite abundant in a protecting wall behind and 

 above but not before the orb. 



These, like other differences in webs, may often be accounted for simply 

 by the fact that they exhibit different stages of completion. Sj)iders do 

 not invariably finish secondary parts of their web at the same 

 Cause of ^[y^■^^^ ji,.jj ^j^py gpj^ ^\^Q primary one. The nest or tent, for ex- 

 ample, will sometimes be a matter of growth, and it is lirobahly 

 the case that the netted cross lines of composite snares are 

 develojied in the same way. Young spiders also differ from adults in the 

 degree of attention which they pay to the secondary jiarts of their snare. 

 The 2>i"incipal part, however, the orb in the case of Orbweavers, is invari- 

 ably completed, if circumstances will permit it, before the spider settles 

 herself to the pursuit of prey. 



