244 



THE NATURE-STUDY REVIEW 



[i, 6, NOV. 1905 



may sometimes be discerned even by human nostrils. The odor 

 may be acid, acrid, rancid, musty, pungent, or Hke that of some 

 vegetable or animal oil. It arises from a substance exuded by 



Camponotus pennsylvanicus worker. Magnification six diameters. From a photograph taken by 

 Mr. J. G Hubbard and Dr. O. S Strong, and retouched by Dr. J. H. Macgregor. From the Bio- 

 logical Bulletin, Vol. VII, p. 308. 



the ants, and it may be transferred from one ant to another^ either 

 by smearing one ant with the juices of another, or by soaking the 

 ants together in a small quantity of distilled water. If an ant 



