30 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 63 



physiological enigma. They are generally absent, but are present in 

 ants and aphidids, are quite abundant in the domestic bee, are present 

 but not abundant in bumble bees, and are absent in wasps ; neverthe- 

 less, he thinks they have nothing to do with olfaction. In dragonflies 

 and cicadas the antennze are rudimentary and the sense of smell is 

 poor. The organs of smell of insects are in general situated in the 

 antennse, especially in their swollen or perfoliate parts where the 

 antennal nerve ramifies. " These ' horns,' these ' ears ' form, there- 

 fore, a famous nose in spite of Wolff and Graber." Thus Forel 

 believes that the antenna; are the olfactory organs, yet he does not 

 state what particular antennal organs receive the olfactory stimuli. 



Berte (1877) states that none of the antennal organs in fleas is 

 for olfaction. 



Lubbock ( 1877) discusses the antennal organs but does not venture 

 to suggest their functions. 



According to Vom Rath (1888), Lubbock (1883) found the same 

 structures on the antennse as did Forel (1874), although the details 

 are somewhat different. Neither Forel nor Lubbock ventures to 

 ascribe an olfactory function to any one of the five antennal organs, 

 but by their many experiments, particularly on ants, both are 

 thoroughly convinced that the antennse carry the olfactory apparatus. 



Graber (1878) describes a pitlike sense organ in the antennse of 

 flies. This was long before described by Leydig as an olfactory 

 apparatus, but Graber regards it as an auditory organ. 



Mayer (1878, 1879) regards the pitlike organs or pore plates as 

 being most probably olfactory in function. 



Reichenbach (1879) thinks that the small pits filled with hairlike 

 structures are the olfactory organs in insects. 



Hauser (1880) studied the behavior of various insects before and 

 after the removal of the antennns. When the antennse were cut off 

 many individuals soon became sick and died, although some of them 

 lived thereafter for many days. In insects with their antennse dipped 

 in melted parafiin, the behavior was similar to that of those with the 

 antennse amj^utated. He placed 12 individuals (beetles) Philon- 

 thus cencHs R. one at a time in an inverted beaker whose bottom was 

 removed. He slowly placed a clean glass rod in front of the head and 

 the insect gave no response. He then repeated the operation with a 

 glass rod dipped in carbolic acid. When this was 4 inches away the 

 insect was much affected, it lifted and moved its head in different 

 directions and made quick forward movements with its antenna. 

 When the glass rod was brought nearer it moved away quickly and 



