106 PECKHAM. [Vol. 1, 



icking them, all cases of such mimicry depend upon the spi- 

 der's increased ability to capture the ants as prey, but I am 

 convinced that this is too hasty a conclusion. It is unquestion- 

 ably true that some birds feed almost exclusively upon ants, 

 but these are the exceptions. It is a common thing to find that 

 specially protected groups, which are safe from the attacks of 

 most creatures, have their special enemies. Thus, even the nau- 

 seous Heliconidfe are preyed upon by certain spiders and wasps; 

 and bees, in spite of their stings, are preferred to other insects 

 by the bee-eaters. Moreover, the ant-devouring birds are found 

 largely among the wood-peckers, which eat the ants that run on 

 the trunks of trees, and are therefore not a source of danger to 

 the ant-like spiders, the American species of which, so far 

 as I can learn, live entirely upon the ground. 



Ill the United States comparatively small numbers of 

 either ants or spiders are eaten by birds, but in tropical Amer- 

 ica there are enormous numbers of humming-birds feeding 

 almost exclusively upon spiders, and there the protective 

 advantage of looking like ants must be of great importance 

 to the smaller species. 



Belt considers that the advantages gained by ant-mim- 

 icking Central American spiders lies entirely on the side of 

 protection. In relation to this subject he says: "Ant-like 

 spiders have been noticed throughout tropical America and 

 also in Africa. The use that the deceptive resemblance is to 

 them has been explained to be the facility it affords them for 

 approaching ants on which they prey. I am convinced that 

 this explanation is incorrect, so far as the Central American 

 species are concerned. Ants, and especially the stinging spe- 

 cies are, so far as my experience goes, not preyed upon by any 

 other insects. No disguise need be adopted to approach them, 

 as they are so bold that they are more likely to attack a spider 

 than a spider them. Neither have they wings to escape by fly- 

 ing, and generally go in large bodies easily found and ap- 

 proached. The use is, I doubt not, the protection the disguise 

 affords against small insectivorous birds. I have found the 



