124 Bulletin Wisconsin Natural History Society. [Vol. 8, No. :j. 



to be communicated through the sense of touch in the antennae) 

 may supersede the trail scent equally well. 



Let me state, therefore, the few examples I have recorded, 

 which seem to bear out this idea of marked change of route of a 

 foray at short notice. In the first place, as we grant the sense of 

 smell to be quite important, it is evident that the observer 

 who cannot see scented trails must be quite familiar with the 

 probable scented trails of all species in the neighborhood of the 

 nests to be observed and tested. While I cannot myself pretend to 

 claim ommiscience as to the unknowable scent trails in such a case 

 for the region of observation, yet the care of this plat and its small 

 size, less than a quarter of an acre, under close scrutiny in ant 

 study for several years, should betoken a fair acquaintance with 

 the subject. And while I could not know the trail scent of every 

 stray ant wandering about the lawn, it was possible, during the 

 two years noted below, to be well acquainted with every regularly 

 travelled trail to a tree, bush or nest, and it was possible to know 

 soon enough of every regular foray from the two nests of san- 

 guined observed. 



If one does not know what the ants of a given nest have been 

 doing above ground throughout a given year, one is not competent 

 to judge whether a trail at its inception is being laid out as a new 

 trail or a trail in use is changed to a stale trail days or weeks old 

 (and no evidence yet shows how long a stale trail retains odor 

 enough for later ants to follow ) . In the following examples, I 

 claim to know nearly all the trails used during the two years in 

 question, and for the two sanguinary nests cited, as I have a 

 couple of notebooks of data of what these two nests did in those 

 two years. 



From this data, I will rirst illustrate by citing instances of 

 straightening out the line of scent of a crooked trail. I will give 

 examples from two different nests, so proving at the same time 

 that such change is not a unique case. Then I will demonstrate 

 from my observations of one of the same colonies how a straight 

 trail may change to a roundabout, crooked, curved trail, and will 

 try to show that the latter example dees not prove as Mark Twain's 

 immortal ant tried to, — that the ants are perfectly inane, — but 

 that it was done for the sake of ease in travelling the trail. If my 

 explanation of the last case is acceptable, it will be seen that we 



