Kew : Snares or Snap-nets of Triangle Spiders. 2 1 1 



the rays only were connected by a symmetrical mesh-work ; ' so 

 that the net, instead of being-, as is generally the case, circular, 

 consisted of a wedge-shaped segment. All the webs were 

 similarly constructed.'* Wilder, independently, has also com- 

 pared the Hyptiotes- snare with the orb-webs of Epeirids, 

 especially with the sectoral-orbs of Nephila and Zilla. Ideally, 

 he says, one may at once draw a comparison between the 

 triangle of Hyptiotes and the orbs of Epeira and Nephila \ for 

 the snare of Epeira is a complete circle, that of Nephila a circle 

 lacking its upper sextant, while that of Hyptiotes is just about 

 the sextant or sixth of a circle: the snare of Epeira is an entire 

 pie, that of Nephila is a pie with a piece cut out, while that 

 of Hyptiotes represents the missing piece : Nephila + Hyptiotes = 

 Epeira. The triangular net, this author thinks, may perhaps be 

 a further specialisation from the sectoral-orb of Nephila, the 

 circle of Epeira being now reduced from five-sixths to one-sixth 

 of its area; and a comparison with the sectoral-orb of Zilla,\ 

 he observes, is even more striking, for if we imagine the Zilla 's 

 snare to be reduced from many radii to four, its free radius 

 clearly represents the trap-line of Hyptiotes. Wilder is not satis- 

 fied, however, that these analogies involve any real zoological 

 relationship; he points out that the Hyptiotes-sna.re differs from 

 others in having a fixed number of radii ; and that the entire 

 independence of the cross-lines is in strong contrast with the 

 spiral or looped cross-lines of the orb-webs. It will be remem- 

 bered that the cross-lines of Epeira consist for the most part of a 

 continuous spiral, and those of Nephila and Zilla of continuous 

 loops running partly round the web, backwards and forwards, 

 turning when the margins of the open sector are reached ; these 

 lines, further, are got into position by means of unadhesive 

 scaffoldings. To be strictly comparable, Hyptiotes would have 

 to lay down a similar scaffolding, and carry the adhesive line 

 backwards and forwards from the upper to the lower marginal 

 radius, from the lower to the upper, and so on in continuous 

 loops ; but, as we have seen, nothing of this kind occurs, the 

 independent cross-lines of Hyptiotes being all commenced on 

 the upper and finished on the lower marginal radius. The 

 nature of the cross-lines, moreover, is absolutely dissimilar : 

 beaded in Zilla and other Epeirids, and flocculent in Hyptiotes ; 

 but the importance of this distinction, perhaps, is diminished by 



* Darwin, Beagle Journal, ed. 1 S4 5 , p. 38. 

 t Epeira calopJiylla. 



igoo July 



