40 F. M. CAMPBELL — OBSERVATIOJIS ON SPIDEES. 



I have had in confinement for twenty-seven months an adult 

 Tegenaria domestica, and she is still alive. On the 13th of last May- 

 she laid about 150 eg^s, and on returning nine weeks afterwards, I 

 found most of them hatched.* The young ones remained in the loose 

 sac which surrounded the eggs until they had cast their first skin, 

 which they did on the third day. I allowed them to he with the 

 mother until September, and never had reason to accuse her of 

 making a meal off any of them, but I cannot acquit her children 

 of this cannabalism. 



Senses. 



The mother-sense, namely, touch, is well developed in spiders. 

 The limbs which are more specially susceptible are the feet and 

 palpi. I have frequently placed a wood-louse [Oni'scus) in a bottle, 

 with a Tegenaria civilis or domestica, and with few exceptions the 

 spider has first struck it with the fore-legs or palpi, and for the 

 time abandoned the prey as if from the knowledge of its being a 

 tough morsel. In all cases, however, the fate of the wood-louse 

 was only a question of time, either from the vigour of the attack, 

 or the entanglement of its legs in the web, which prevented its 

 assuming its usual protective attitude. Spiders are, moreover, well 

 provided with the means of feeling the slightest movement of their 

 webs or other objects. On their legs and palpi are long slender 

 simple hairs, which differ from others in that they are attached to 

 a small disc on the integument. They are numerous on the Epeira 

 diadema (garden spider), and are unusually long on the palpi of the 

 Pholcus phalangioides (cellar spider). In web-spinning species they 

 appear to rest on the snare, and this may account for the accuracy 

 with which these spiders estimate the strength of their victim, 

 while it also enables them to avoid risking an encounter of doubtful 

 result. A violent agitation of the threads would at once show 

 them they had no easy victory before them. It is also quite possible 

 that these hairs are affected by the vibrations of sound ; but as the 

 organs of a special sense are always localised, it is unlikely that 

 the sensation a spider receives by such means is anything more 

 than one of disturbed stability. "\Ve ourselves, whose sense of touch 

 has not been especially developed in this direction, can, by placing 

 our hands, for instance, on a wooden structure near an organ, ex- 

 perience the vibrations of sound in the form of a gentle tremor, 

 which is different to all other sensations. In a similar way some 

 deaf people are enabled to enjoy music, and as there has as yet 

 been nothing found on spiders which can be called an ear, we may 

 not be wrong in attributing the undoubted effect on spiders of 

 sound-vibration to the presence of the hairs which here I have 

 briefly described. 



* As I send this paper for publication (May 13th), I notice that early this 

 morning the same spicier has spun a shaft 3 J inches in height, H inches in diameter, 

 from the bottom of her bottle, and has supported it with side attachments. On 

 the top she has laid one egg only, and covered it with a close-spun sheet an inch 

 in diameter. The coincidence of the dates is strange. 



