332 SOME NEW ARANEIDiE OF N.S.W., 



charred iDranches or bark that when motionless it is utterly 

 impossible to perceive them.* In some species the modification is 

 very gcadual, while in others the change is more i^apid. An 

 American author, Mr. J. Angasf states that when he placed a 

 white variety of what he terms the " little flower spider " on a 

 sun-flower it became quite yellow in from two to three days. 



The habit of lying motionless when alarmed is common among 

 sedentary spiders, such as the Epeiridce. and Theridiidoi; but it is 

 badly developed in some and entirely absent in others of the 

 jumping and swift-running species. Among the orb weavers the 

 Gasteracanthidce are singularly and effectively protected against 

 the raids of insectivorous birds. Resting in the centre of their 

 orbitular snares, fully exposed, the need of a protective armature 

 is obvious, and this is afforded by their hard, horny and spiny 

 abdomens. Likewise, the spines of Acrosonia, rendering the 

 spiders similar in appearance to thorny leaves, knots of shrubs, 

 acacias, &c., are also protective, and make these animals decidedly 

 objectionable to insectivorous birds and reptiles. As in the case 

 of the G aster acanthidce, the spiders of the genus Acrosoma also 

 construct their webs in exposed situations, and sit fearlessly in 

 the centre of the snares as though conscious of their security from 

 attack. 



In many instances specimens, when viewed in the cabinet, 

 would not be likely to suggest the idea that their form and 

 colouration are protective, yet when observed in the midst of 

 their natural surroundings the fact that such is the case is forced 

 upon the observer. Again, some specimens lose their natural 

 colours when placed in spirit. This is the case wdth Epeira 



* Mr. A. T. Urquhart in an interesting paper observes that "The 

 generality of spiders found amongst burnt manuka, before it has become 

 bleached, have the brownish-black colour of their environment, wliich 

 causes them to be almost imperceptible at a very short distance." — "On 

 the Protective Resemblances of the Araneidea of New Zealand," Trans. 

 N.Z. Inst. Vol. XV. 1SS2, p. 175. 



t " American Naturalist," xiv. p. 1010. 



