290 OSV. POLIMANTI 



considered these odors a means of sex attraction. Leoni, how- 

 ever, found them present in both males and females and in- 

 terpreted them as a means of recognition among individuals of 

 the same species. 



Fabre 3 carried on some experiments, to determine this point, 

 with Satumia pyri and Gastropacha quercus. He placed a 

 female of Satumia in a cage of wire netting. During the night 

 the cage was surrounded by males of the same species. To 

 ascertain whether it was by means of the antennae that the 

 odor was perceived by the males, he cut off their antennae and 

 moved the female to another room. On the following night 

 only one of these males with amputated antennae was found 

 in the number which flocked around the cage. This fact might 

 be due, however, to the short life of the adult male. In all, 

 Fabre captured, during eight evenings, one hundred and fifty 

 males, which was the more remarkable because very few indi- 

 viduals of this species had been known in that vicinity, and very 

 few cocoons had been found. Some of the moths must have 

 come long distances. Fabre explained the phenomenon by the 

 existence of emanations insensible for us but capable of influenc- 

 ing an olfactory sense more acute than ours. He experimented 

 also with receptacles, for the female, of different materials, of 

 tin, wood and pasteboard, and found that only when these 

 were hermetically sealed did the males fail to find the female. 

 Nor did the attempt to mask the odor by means of other strong 

 odors, like those of naptha, essence of nard, petroleum, carbon 

 disulphide, have any different result. When the female was 

 placed under a glass shade, the males paid no attention to her, 

 but hovered around the cage in which she had previously been 

 confined. In this last experiment, it became evident that sight 

 had nothing to do with attracting the males. These experiments . 

 were repeated later by Fabre with Bombyx. 



The experiment of cutting off the antennae of the oak eggar 

 {Gastropacha quercus) gave doubtful results. The grass eggar 

 {G. trejolii) showed less acuteness in discovering the female. 

 The existence of a special odor in the female of Satumia and 

 Gastropacha quercus was, however, thoroughly established by 

 Fabre's experiments. How these odors are perceived remains 

 to be solved. It is difficult to imagine any substance which, 



3 Fabre, J. H. Souvenirs entomologiques. Paris. T. 4. P. 56. 



