THE OLFACTORY SENSE OF INSECTS 



By N. E. McINDOO, Ph. D., 

 bureau of entomology, washington, d. c. 



CONTENTS PAGE 



Introduction I 



Sense of smell in general - 



Spiracles as seat of olfactory organs 3 



Structure near spiracles as seat of olfactory organs 5 



Glands of head and thorax as seat of olfactory organs 6 



(Esophagus as seat of olfactory organs 6 



" Internal superior surface " as seat of olfactory organs 7 



Different parts as seat of olfactory organs 7 



Folded skin beneath antenn?e as seat of olfactory organs 7 



Rhinarinm as seat of olfactory organs 7 



Plate between eyes and beneath antennae as seat of olfactory organs 8 



Mouth cavity as seat of olfactory organs 8 



Epipharynx as seat of olfactory organs 9 



Palpi as seat of olfactory organs 9 



Antennae as seat of olfactory organs 



( 1 ) Without experiments 1 1 



(2) With experiments 14 



Various structures on antenn.-e as olfactory organs 24 



Caudal styles (" abdominal antennae ") as seat of olfactory organs 35 



Organs on bases of wings and on legs as olfactory organs 36 



Olfactory organs on the appendages and sternum of spiders 49 



Summary of author's experiments 51 



Literature cited S6 



INTRODUCTION 

 Since no one has ever collected the views of the various writers 

 on the sense of smell in insects, the literature that bears directly on 

 this subject is here briefly discussed for the use of students on this 

 subject. Abstracts and translations of this literature have been 

 made by the writer and his wife, Emma Pabst Mclndoo, and the dis- 

 cussion is from these abstracts and translations. Minor details may 

 have been incorrectly stated in some cases, but it is believed that each 

 view as a whole is given correctly. The views of a few authors have 

 been cited from others, because the original works were not access- 

 ible. After a short discussion of the sense of smell in general, the 



Smithsonian Miscellaneous Collections, Vol. 63, No. 9 



