NO. 2 RECOGNITION AMONG INSECTS — McINDOO 3 



little about the senses of hearing and taste in the lower animals, we 

 may safely eliminate them as the chief factors in recognition. 



That the lower animals do recognize one another without using 

 the tactile organs, and as their sense of sight is not sufficiently 

 developed to be the chief factor in recognition, we may assume that 

 the most important factor is some chemical sense, perhaps similar 

 to our olfactory sense. If the olfactory organs are the chief means 

 of recognition, they must constantly receive stimuli in the form of 

 odors, and these odors must be emitted by the animals themselves. 

 If this is true, it would seem that the odor emitted by one animal 

 should be at least slightly different from that of any other animal, 

 and reasoning in this way Jaeger (1876) believes that most animals 

 emit odors peculiar not only to the individual, variety, race, and 

 species, but also to the genus, family, order, and class, and that 

 these odors are the chief means by which one animal recognizes other 

 animals. Without the aid of the eyes he claims that the degenerate 

 human olfactories are able to distinguish a horse from a cow, a goat 

 from a roe, a dog from a cat, a martin from a fox, a crow from a 

 pigeon, a parrot from a hen, a lizard from a snake, and even a carrion 

 crow from a hooded crow. Blackman (1911) remarks that the 

 anal mucous membrane of our domestic animals, particularly the 

 dog and cat, contains glands whose secretion emits a comparatively 

 mild odor which probably serves as a secondary sexual purpose, 

 but in other carnivores, such as the otter, badger, wolverine, mink, 

 martin, ferret, ermine, weasel, and skunk, the scent may be far from 

 mild and in many cases is used either as a means of defense or 

 offense. 



The chief object of the present paper is to show that the chemical 

 sense (usually called the olfactory sense) in the lower animals, but 

 particularly in the honey-bee, is so highly developed that we do not 

 have any more conception of it than does the honey-bee (if it could 

 think as we do) of our wonderfully developed sense of sight which is 

 able to distinguish accurately the size, form, and color of objects. 



If recognition among the lower animals is accomplished by means 

 of odors stimulating the olfactory organs, then these animals must 

 have means of producing the odors, and therefore such organs may be 

 called scent-producing organs. The experimental results embodied 

 in the present paper are mostly from observations made upon the 

 honey-bee by the writer, while the part dealing with the scent- 

 producing organs is a brief historical review of the literature on 

 this subject. 



