74 THE entomologist's RECORt). 



The mimicry of gaiests associating with blind or nearly blind ants 

 txkes quite a different form, as it only seeks to deceive the sense of 

 touch. It begins with a similarity of structure and hair-grow^ths be- 

 tween guest and ant, and develops into a close similarity of form in 

 the different parts of the body, more particularly in the antennae. The 

 best examples are to be seen in the Eciton guests of Brazil. The 

 notorious " wander-ants," the terror of all small animals, belonging to 

 the neo-tropical regions, have in their suite a number of different 

 guests, especially beetles belonging to the Staphylinidae, who accom- 

 pany these robber-bands, either on foot or riding on the egg-clusters. 

 In 1891 I had already described twenty-one species of Eciton guests, 

 and since then several very remarkable species have been sent to me. 

 Mimicry plays the principal part in assisting these guests to live in 

 such dangerous society. Not only do they receive no harm, but they 

 are even allowed to help themselves to the prey and offspring of their 

 thievish hosts. Eight of these twenty-one species of Eciton guests 

 mimic their hosts. It can be proved that these are cases of true 

 mimicry {i.e., to deceive their hosts) by comparing them with the 

 mimicry of guests of clear-sighted ants. The former deceive the host's 

 sense of touch in the same way that the latter deceive the host's sense 

 of sight. Eciton mimicry reaches its highest state of perfection in 

 Ecitomorplui aimulcnn, Wasm., a guest of Eciton foreli, Mayr, and in 

 Mimecitoii 2'nle.T, Wasm. (pi., fig. 4), a guest of Eciton praedator, Sm. 



A superficial glance would not suffice to understand this kind of 

 mimicry, as the similarity is not calculated to deceive the sight but the 

 touch. It is necessary to place each part of the mimic's body under 

 the lens, and compare it with a similar part of the body of the smallest 

 worker-ants of the host. One will then recognise a true Eciton mimic, 

 whereas, to the naked eye, by the side of the glossy-black ant it looks 

 like a long-legged ruby-red flea — hence its name "pulex." The 

 mimicry here exhibited is so perfect that by closer observation one 

 would think one had a real ant before one instead of a beetle. Its 

 head is shaped like a small Eciton head, its thorax stretches out and is 

 narrowly arched like the back of an Eciton and contracted exactly in 

 the same place as the ant's thorax, and on both there is a large 

 fissure. Then there comes an apparently unconquerable obstacle. 

 IIov/ is the very broad knotty-shaped first segment of the double- 

 ringed hind-body of the ant to he represented by a beetle that should 

 possess elytra in this identical spot ? The elytra of the Mhneciton are 

 no longer elytra because they do not cover any wings, nor have they a 

 suture. They form a knotty shaped roof, from under which the 

 narrowed base of the abdomen proceeds in the same manner as the 

 second part of the abdomen of the Eciton. The abdomen is fat and. 

 arched like that of a well-fed ant, and the antenn® are whip-shaped 

 and have a long first joint identical with those of the ant. To make: 

 the mimicry perfect the beetle has even lost its compound eyes, which 

 are replaced by tiny ocelli like those of the ant. It has the long spider- 

 legs of the wander-ant, but this also serves it for a practical purpose,, 

 i.e., to keep up when running in company with these capricious- 

 vagabonds. What is even still more astonishing is the fact that the-^ 

 comb-shaped spur on the extremity of the ant's anterior tibia? is repro- 

 duced in the beetle by a spur-shaped hook (see pL, fig. 4). If therc^ 

 are anywhere in nature examples of true mimicry, they are to be found 



