SMELL. 227 



of antennae. Forel pointed out that the numbers were not sufficiently 

 different to prove much, and this is confirmed by the fact that the respective 

 percentages for meat were 64 and 72. In addition, the odor of putrid 

 meat in a box was regarded as sufficiently strong to provoke tactile or 

 gustatory reactions quite apart from smell, while flies inclosed in a box 

 are far from normal in their response. With Formica rufa, Graber found 

 that essence of rose was not liked, 515 ants collecting in the empty division, 

 and but 42 in that containing the essence, while with the antennas cut off 

 the respective numbers were 299 and 165, figures which Forel regarded 

 as insufficient to prove that ants have other organs of smell than antennas. 

 However this may be, he declared that Graber had absolutely not proved 

 that ants with or without antennas were in a state to recognize the essence 

 of rose as such, to distinguish it from another substance, or to find it when 

 hidden. Finally, in another place Graber seemed to be of the opinion 

 that these responses were rather of the nature of reaction to irritation 

 than smell. In the case of Silpha thoracica, while essence of rosemary 

 quickly produced a reaction in the absence of antennas, asafetida did not, 

 but with the antennas present the response to both was equally prompt. 



In summarizing, Forel declared that the experiments of Graber ex- 

 hibited a very superficial knowledge of the habits of insects, often lacked 

 controls, and were too little varied, and that the means and the reagents 

 employed were frequently too strong and took no account of the habits 

 or needs of each species. Moreover, after seeking the location of the sense 

 of smell in various places in contradictory fashion, Graber finally stated 

 that "there are insects in which the antennas play a preponderant rdle 

 in the distinction of weaker odors, food, etc." 



In a later paper (1887:13) Graber himself stated that the stronger 

 odors usually repel insects and that this response is not due to the sense 

 of smell, but to a generally very painful excitation of the sense of feel, 

 which is often extraordinarily developed. As a consequence of a number 

 of carefully controlled experiments, he reached the conclusion that Plat- 

 eau's results with the cockroach (1876) were untrustworthy, though he was 

 able to confirm the statement that the sense of smell is located in the 

 antennas. 



Hauser's experiments. — Hauser (1880:367) determined the effect of 

 removing the antennas in a wide range of insects from beetles to bees. 

 The loss of the antennas caused many individuals to become sick and die, 

 though some lived for weeks afterward. Coating the antennas with paraf- 

 fin gave the same results as extirpation. Beetles made no response to 

 a clean glass-rod, but when this was dipped in carbolic acid, the effect 

 was noticed at 4 inches and the insect moved away quickly as the rod 

 was brought nearer. It reacted even more strongly to turpentine and 

 acetic acid. The experiments were repeated on the second day after the 

 removal of the antennas, but no response occurred. This was in spite of 

 the fact that the beetles ate more heartily after the operation and some 

 lived more than two months. Species of various genera gave similar re- 

 sults, but a few continued to respond slightly. Beetles of the genus Silpha 

 lost the power of finding putrid meat after the amputation of the antennas, 

 and the same result was obtained with different species of flies. Male and 



