1881.] 



NATURAL SCIENCES OF PHILADELPHIA. 



16T 



II. Mode of Operating the Snare. 



When an insect strikes the snare, the spider has two modes of 

 operating. The first somewhat resembles that of the ordinary 

 orb-weaver in that the insect is simply permitted to entangle itself 

 and is then taken, swathed, returned to the centre and eaten. 

 There is, however, this difference : before going to the insect, the 

 axes of the snare are twisted or knotted, by a rotary action of the 

 body and movement of the legs, so that the untouched parts of 

 the orb remains taut. Fig. 2 represents a snare thus " locked,"' 



Fig. 5. 

 or, perhaps I might more properly say, " keyed." The trap-line 

 is now relaxed, although its elasticity is such that the change can 

 scarcely be noticed. The spider then moves upon her victim, 

 quite habitually cutting out the spirals with her mandibles as she 

 goes. When the insect is ensnared well towards the circumference 

 of the web, and indeed, for the most part, in other cases also, it 

 results that the ray or sector upon which the entanglement had 

 occurred, is quite cut awaJ^ The spider thereupon proceeds to 

 operate the remaining parts of her snare, which, in time, is thus 

 destroyed by sections, as will be fully illustrated hereafter. 



