MIMICRY IN SPIDERS. 



375 



Protect 

 ive Re- 

 sem- 

 blance. 



since tlie colors of lier body, as well as its shape, correspond well with 

 the colors of the egg sac. We might, therefore, regard this as a case of 

 protective mimicry. This scalpage is never in the shape of re- 

 served stores of food, as Lister seems to think, and therefore 

 cannot be cited, as by Kirby and Spence,i to show that Conica 

 is " more provident than its brethren." Those distinguished en- 

 tomologists should have known that spiders do not feed upon 

 the hard shells of dead insects. 



This mode of disposing of the fragments of her feasts is not limited 

 to Caudata's cocoons. Like her English congener Conica, as described by 

 Lister, she hangs tliose remnants upon her snare. I often see orbs througli 

 the middle of which are stretched, above and below the hub, a perpendic- 

 ular ribbon of open fibre. Along this will be attached two or three little 

 conical balls above and below the hub (see Fig. 319), composed of the 

 members of dead insects cut into fine particles and lashed together by 

 threads. May we venture to suppose that this also is a 

 case of mimicry, that is to say, a purpose to set up " dum- 

 mies " to distract the attacks of hymenopterous and other 

 enemies from her own person? 



I have met a like behavior in Acrosoma rugosa. The 

 web was a small one, five inches in diameter, spun between 

 the branches of a fir tree. Around the margin 

 the remains of seven flies were threaded, much 

 in the fashion above described. Three of tli^ese 

 were above and three below the centre. They 

 appeared to be mere shells, not fresh insects trussed up for 

 future use, as one often sees when flies are plenty. They 

 had not simply become thus entangled when cast out from 

 the web, for tliree of them were fastened above the centre, at which 

 the spider sits, and the four below were arranged along the arc of a 

 circle in such order and jjosition as to indicate design. I never met this 

 peculiarity in the snare of Rugosa except in this one case, and have not 

 observed anything like it in any other species. As a habit it exists in 

 Caudata alone. 



The young of Caudata, as I have frequently noticed, have precisely the 

 same curious habit that marks the adults, to string along the central band 

 of their webs fluffy, loose bunches of silk, covered with little particles of 

 trapped insects, which increase in size as she grows. Mrs. Mary Ti'eat has 

 observed the same habit. ^ The transmission and early possession, in full 

 force of such an exceptional and remarkable habit, is peculiarly note- 

 worthy, and, except on the theory of protective mimicry, it perhaps would 

 be difficult to suggest any useful purpose in the habit. A gentleman 



Acro- 

 soma 

 rugosa 



Fig. 319. Balls of 

 insect debris in 

 Caudata's snare. 



• Introd. Ento., I., 421, 



' My Garden Pets," page 42. 



