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 like 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 



