20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 63 



and fifth, the odor of enemies. Miss Fielde ( 1903b) claims that feuds 

 between the same species Hving in different communities are caused 

 by a difference of odor. Also, (1904) fear and hostility are excited 

 by a strange ant odor. She (1905) decides that ants have a specific 

 and progressive odor ; the former is received by organs near the 

 proximal end of the funiculus, while the latter is received among 

 ants by organs in the penultimate joint of the funiculus. 



Pieron (1906), basing his conclusion on the interpretations of 

 F'ielde and others, remarks that recognition in ants by odor is well 

 established, and that sections of the antennze have shown that the 

 organs of smell are those of recognition. 



Wheeler (1910) believes that the olfactory organs of ants are 

 located in the antennae, but he refutes Miss Fielde's theory that each 

 segment of the antenna perceives a particular odor. He asserts : 



She sa3's : " The organ discerning the nest-aura, and probably other local 

 odors, lies in the final joint of the antenna, and such odors are discerned 

 through the air ; the progressive odor or the incurred odor is discerned by 

 contact, through the penultimate joint; the scent of the track by the ante- 

 penultimate joint, through the air; the odor of the inert young, and probably 

 that of the queen also, by contact, through the two joints above, or proximal 

 to those last mentioned, while the next above these also discerns the specific 

 odor by contact." 



This statement not only lacks confirmation by other observers, but seems 

 to be the only one which implies that the olfactory organs of an animal may 

 exhibit regional differentiations. This has not even been claimed for dogs, 

 which nevertheless possess extremely delicate powers of odor discrimination 

 and association. This would be no serious objection, however, if we were 

 able to discover the slightest support for Miss Fielde's hypothesis in the struc- 

 ture of the antennae. We do, indeed, find in the funiculi a variety of sensillas, 

 as has been shown in Chapter IV, but none of these is confined to a single joint 

 or to two joints. ]\Iiss Fielde, moreover, completely ignores the tactile organs 

 of the antennae and makes this surprising statement : 



" During five years of fairly constant study of ants I have seen no evidence 

 that their antennae are the organs of any other sense than the chemical sense." 



Many of her interpretations of the behavior of ants with mutilated antenna 

 are open to the obvious objection that she tacitly denies the existence of per- 

 ception where there is no visible response or where the animal inhibits certain 

 of its activities. If we add to this objection the very limitations of the method, 

 i. c, the necessity of removing all the joints distal to the one whose function 

 is being tested, and the consideration that the hypothesis is not needed to 

 explain the facts, it will be seen that we are not sufficiently justified in re- 

 garding the ants' antenna as an organ made up of a series of specialized 

 " noses." 



Barrows (1907) says: 



I have found that Drosophila auipelophila (the vinegar fly) has a large 

 saclike pit, which contains sense cones, situated in the end of the terminal 

 (third) segment of the antennae. 



