MIMICRY IN SPIDERS. 361 



these flying spiders into their crops, where they have been found in quan- 

 tities. Certainly, a resemblance of an ant form could be of no avail here. 



Again, the theory compels us to assert that ants are not subject to de- 

 struction by birds. Of course, unless this be true we can conceive of no 

 advantage in the mimicry of an ant form as protecting the spi- 

 ir der against birds that seek to devour it. Its safety lies in the 

 ' fact that it is covered from harm by its likeness to an insect 

 which birds avoid. On the contrary, I know that some birds certainly 

 do eat ants, and eat them greedily. 



Mr. Carl Voelker, of Carlingdale, Delaware County, Pennsylvania, is a 

 taxidermist of large practical experience, and with a fondness for natural 

 history which prompts him to make and note observations upon the gen- 

 eral habits of birds and other animals. He has informed me that the 

 flicker, Picus auratus, at certain seasons of the year in the spring, for 

 example will station itself upon a dead stump, which in our American 

 woods is frequently infested with ants, and feed greedily upon them as 

 they pass to and fro. This he has observed many times, and believes 

 that at certain seasons this bird lives entirely upon ants. He has seen 

 two species devoured by them in the manner above described a little 

 black ant and one about twice as large. 



The pileated woodpecker, Picus pileatus, feeds quite habitually upon 

 the large black Pennsylvania carpenter ant, Camponotus pennsylvanicus. 

 He has frequently taken these insects, in various stages of decomposition, 

 out of the crops of these birds, at one time having counted nearly seven 

 hundred in the crop of a single woodpecker. The bird not only takes 

 the ants in the summer, but also in the winter, and Mr. Voelker has seen 

 them stationed upon trees, pecking at the gangways or gates into the for- 

 micaries until they had been hammered open, and then extracting the 

 ants while they were in a torpid state. As some of these homes in forest 

 trees are extensive bits of architecture and are inhabited by vast numbers 

 of insects, the amount of food thus obtained must be considerable. In the 

 forests of Pennsylvania I have seen formicaries of the carpenter ant six 

 feet in length and occupying the entire central part of a goodly sized 

 tree or branch. 



The European woodpecker, Picus ater, according to the same gentle- 

 man, who has observed the same species in Germany, subsists 

 The entirely upon ants, and the same fact is true of another Euro- 



, " pean species, Picus virens, popularly known as the Grass Wood- 

 pecker. Mr. Voelker has seen this bird on the hills of Germany 

 digging into the soil, and feeding eagerly, not only upon the larvae, but 

 upon the ants themselves. 



It is generally known that the ordinary barnyard fowl will devour ants 

 without hesitation. Mr. Voelker states that once he w r as engaged in the 

 woodyard of his country residence in breaking up a log of decayed wood 



