MIMICRY 373 



Such resemblances, obvious enough in nature, and heightened 

 by the behaviour of the mimetic form, are often by no means 

 striking in the cabinet. In some American species of spiders, 

 however, imitation of the ant has passed beyond the stage of a 

 general resemblance as regards size and colour and method of pro- 

 gression. The head of the ant is well marked off from the body, 

 and the thorax is frequently divided into distinct regions. These 

 peculiarities are imitated by constrictions in the cephalothorax 

 of mimetic spiders. The resemblance, moreover, is much increased 

 by their habit of using but six legs for locomotion, and carrying the 

 second pair as ants do their antennae. The best known examples 

 of these spiders are Synageles 2ncata and Synemosyna formica (see 

 Fig. 215, C, p. 420), and even more striking resemblances have been 

 observed among some undescribed South American species. 



The object of such mimicry seems to vary in different cases. 

 Sometimes the spider preys upon the ant which it resembles. 

 Sometimes, again, by its disguise, it escapes the notice of the ant 

 which would otherwise feed upon it. More often spider and ant 

 are neutral as regards each other, but, under cover of its resemblance, 

 the Arachnid is enabled to approach an unsuspecting victim to 

 which the ant is not a terror. Again, the unpleasantly acid taste 

 of ants is unpalatable to most birds, though not to all, and the 

 increased danger from specially ant-eating birds may be more than 

 counterbalanced by the immunity they acquire from other birds. 



There is quite a large class of Spiders of nocturnal habits, whose 

 only precaution by day is to sit perfectly still and be mistaken 

 for something else. We have referred to the adaptation in 

 colour of our English species, Misumena vatia, to the flowers in 

 which it lies in wait for prey. Bates ^ mentions exotic examples 

 of the same family which mimic flower-buds in the axils of 

 leaves. Herbert Smith says of a spider which sits upon a leaf 

 waiting for prey : " The pink three-lobed body appears just like 

 a withered flower that might have fallen from the tree above ; 

 to the flies, no doubt, the deception is increased by the strong 

 sweet odour, like jasmine." 



Trimen ^ describes a Cape Town species which is of the exact 

 rose -red of the flower of the oleander. "To more effectually 

 conceal it, the palpi, top of the cephalothorax, and four lateral 



^ Naturalist on the Amazon, 1873, p. 54. 

 ^ Protective Resemblances and Mimicry in Animals, 1873, p. 4. 



