72 Journal New York Entomological Society. [Voi. v. 



it falls to the ground it will walk about precisely like the wasp it seems 

 to resemble the most closely, so that its actions constitute by far the 

 greater portion of the mimicry, and therefore are to the greatest extent 

 protective in effects. 



Among those species which resemble ants the most closely, and ap- 

 pear to derive protection therefrom, we find that, besides a more or less 

 close resemblance in form and color, they have the erratic, rapid move- 

 ments of such species of ants as they most resemble. Pilophorus bifas- 

 ciatus Fab., a species of Hemiptera which is here in Ohio frequently as- 

 sociated with a species of black ant that is common and very often ob" 

 served running up and down the trunks of trees and out on the limbs 

 and twigs, does not closely resemble one of these ants when pinned and 

 placed in the cabinet of a collector ; but when running about over the 

 trees they have the quick, erratic movements of the ants, and are then 

 very difficult to distinguish from their associates.* In this case the de- 

 ception is largely due to movement, and but for this there would be little 

 resemblance. Belt, in "The Naturalist in Nicaragua," p. 314, speaks 

 of a species of spider that appeared so exactly like a species of stinging 

 ant that he did not distinguish the difference until he had killed the 

 spider, and adds that "the resemblance is greatly increased by the spider 

 holding up its two fore legs, like antennce, and moving them about just 

 like an ant." 



Not over a couple of hundred yards from where I am now standing I 

 was some years ago collecting small insects from the leaves of an elm tree, 

 and saw what at a glance I took to be the excreta of a bird on the upper 

 surface of a leaf, and, avoiding it, was busily engaged with my collect- 

 ing. On making a sudden thrust I brought my hand in direct contact 

 with the leaf, and not perceiving any excreta on my hand looked for an 

 explanation, when, to my utter astonishment, the larger portion of the 

 supposed excreta was observed to take legs and run across the leaf, and 

 I found that it was nothing more or less than a small spider, whose back 

 was clouded with a blackish area, surrounded with white. A white 

 splotch remaining on the leaf proved to be only an irregular sheet of 

 spider web, but almost exactly counterfeiting the appearance of semi- 

 liquid bird excreta that had become dried, and I saw at once through 

 the whole deception. Taken separately, the spider was easily recog- 

 nized, but placed on its sheet of thin white web and the deception was 



* In this case the rays of light reflected from the polished, black surface of the ab- 

 domen of the ant, appear like a transverse whitish band, very like in appearance to 

 the transverse white fasca: on the wings of the bug. 



