172 [August, 



but which Mr. Saunders treats as mere varieties of it, spinigera, 

 eximia, austriaca, &c.) should be regarded as very near relations, while 

 bucephala, being utterly unlike any of them, both in its armature and 

 its 8th ventral segment, can hardly be admitted to a place in the same 

 group. But I quite feel that the special attention I have given to 

 these characters, and the interest I have come to take in them, may 

 make me exaggerate their importance. 



As to the fact, however, that in these points ferox closely re- 

 sembles rosce, &c, and does not in the least resemble bucephala, there 

 can be no doubt whatever, and I therefore put the fact on record, be 

 its interpretation what it may. 

 Woking : July, 1902. 



A REMARKABLE INSTANCE OF DELIBERATION OBSERVED IN 



AN AMERICAN ANT. 



BY C. R. OSTEN SACKEN, Ph.D., Hon. F.E.S. 



It was in Albany, N. T., more than forty years ago, that I found 

 myself confined during a rainy day in a small hotel room with white- 

 washed walls. I soon noticed a small brown ant walking upon the 

 wall, and it occurred to me to follow its path by drawing it with a 

 lead pencil. The line thus drawn by me ran upwards for a certain 

 distance, and then, in a broad curve, turned towards the right. The 

 next morning I saw an ant of the same kind follow the same path ; 

 as I had some ether with me I put a small drop of it upon the pencil- 

 line which I had traced the day before, but at a considerable distance 

 in advance of the approaching ant; as soon as the ant smelt the ether 

 it abandoned the path, turned to the left, and changed its mode of 

 progress. Instead of going straight ahead, it now moved in zig-zags, 

 making gradually longer those branches of the zig-zags which were 

 directed towards the right. By adopting this course the ant again 

 met, by and by, the line I had traced ; it recognised immediately what 

 seems to have been the highway for ants travelling on that wall, and 

 followed it to the end. 



It is evident that in this instance the ant, in recognising its road, 

 was guided neither by its eyesight, nor by its sense of touch, but by 

 the sense of smell, or some sense akin to it. But the resolute action 

 of the ant in quitting a path which it could no more follow, and 

 retrieving it afterwards, at another place, by a different and well 

 considered course of progress, offers, it seems to me, a remarkable 

 instance of the power of deliberation in an insect. It is probable 

 that most ants, in a certain degree, possess this power. ^ 



