MR, E. I. POCOCK — MIMICRY IN SPIDERS. 259 



the Clubionid, Micaria scintillans, presents the closest resemblance to a large 

 black ant [_Forinica rufihai'Us'] with which it associates. 



Two North- American species o£ Salticidse (Peckhamia picata and Synemo- 

 si/na formica) have been closely studied by Mrs. Peckham *, who states that 

 the former presents a general resemblance to ants o£ two or three species 

 with which it associates indiscriminately. Like an ant, when hunting for 

 prey, the spider always zigzags from side to side in its walk and holds up the 

 legs of the second pair in front of the head to simulate a pair of antennae. 

 Instead of standing still while feeding, as most spiders do, this spider keeps 

 up an incessant twitching of the abdomen, pulling about its prey in different 

 directions the while, beating it with its fore legs, and imitating to the life the 

 restless movements of an ant when similarly engaged. Synemosyna formica 

 behaves in exactly the same way as P. picata, although without mimicking 

 the zigzag walk of the ants. 



A few more records may be quoted. In the Oriental Region there is a 

 common red-and-black tree-ant, Sima rvfo-nigra. It is pugnacious and 

 fearless, attacking without hesitation almost any animal it meets. On human 

 beings the effects of its bite are both painful and lasting. "Wherever these 

 insects occur in any numbers, a species of spider [^MyrmaracJine providens], 

 one of the Salticidas, is to be found runniug about amongst them. The 

 spider closely resembles the ant in form and colour. It appears to be on the 

 most friendly footing with its formidable associates, moving quickly here and 

 there in their company and copying their busy, hurried actions f- Again, 

 there is in India a spider, of unknown identity, almost indistinguishable from 

 the female of an ant, Camponotus opaciventris, whose mode of progression by 

 a series of rushes and pauses the spider imitates closely ; and in the neigh- 

 bourhood of almost every strong colony of another ant, Cremastogaster co7itenta, 

 a mimicking spider is to be found, moving about at a jog-trot and waving its 

 abdomen in the air in exact imitation of the actions of its model. Again, in 

 South Africa Mansell Weale J discovered two species of Attidse which bear 

 the closest resemblance to ants. One is smooth, black and shining, and runs 

 rapidly over the ground and on the bark of trees, and resembles an ant 

 that builds its nests on acacia-bushes. The other is larger and has its cephalo- 

 thorax dull black and its abdomen covered with short yellowish hairs. It is 

 generally found running on the stems of herbaceous plants, and closely 

 imitates an ant found in similar situations. The fore legs in both are 

 frequently held up so that they closely resemble the antennae of an ant. 



As might be expected, ant-mimicry is of much commoner occurrence amongst 

 ground-living species of spiders, belonging to the so-called " wandering- 

 tribes " which spin no snare, than it is amongst the snare-spinning sedentary 



* Occ. Papers Nat. Hist. Soc. Wisconsin, 1889, pp. 110-113. 

 t Rothney, J. Bombay Nat. Hist. Soc. vol. v. p. 43, 1890. 

 X ' Nature,' 1871, p. 20. 



