THERE is no doubt that many insects have a sense of smell, but there is great variety of opinion as to the precise location of the sense. Dr. N. E. McIndoo,1 of the Washington Bureau of Entomology, has summed up the discrepant views in forty pages, and also in one word—“chaos.” Lehmann seems to have been the first to experiment (1799), and he was led to the conclusion that the seat of smell is in the spiracles. Most of the older naturalists reached their conclusion without experimenting, and the sense of smell has been referred to at least a dozen different parts, such as the mouth, the epipharynx, the palps, the caudal styles. Of recent years, as the result of experiment on one hand and histological analysis on the other, there has been a tendency to conclude that the antennae are the olfactory organs. The antennae are rich in sensory structures, and their removal is sometimes followed by a negative reaction to an odour which is attractive to the intact insect. Dr. Mclndoo thinks that the arguments are very inconclusive.
â œThe Olfactory Sense of Insects.â By Dr. N. E. McIndoo. Smithsonian Miscellaneous Collections. Vol. lxiii (1914), number 9. Pp. 1â 63, 6 figs.