l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 63 



Graber (1885) severely criticizes the view that the antennas are 

 the seat of the olfactory sense. He experimented on many species 

 with various odors, and makes the following claims: (i) Ants 

 (Formica rufa) and flies (Lucilia caesar L.) without antennae still 

 possess the sense of smell ; this fact shows that the perception of odors 

 is not accomplished by the antennae alone. (2) In Silpha thoracica 

 deprived of antennae, the odor of the essence of rosemary is mani- 

 festly perceived, while assafoetida does not afifect the insects at all. 

 Thus the antennae are those parts of the body which are most sensible 

 to odors. (3) From the comparative experiments on the excitability 

 of the antennae, the palpi, and the cerci (caudal styles) in Gryllotalpa 

 gryllotalpa L. (vulgaris), the palpi are more sensible to odors than the 

 antennae. (4) The palpi of Lucanus are sometimes the most easily 

 excited, at other times the antennae, according to the odors employed. 

 From similar experiments on Periplaneta, some intact, others several 

 days after they were operated on, it seems that the reception of odor 

 stimuli is accomplished by the cerci. Graber is inclined to the view 

 that insects do not have any special olfactory organ, and that when 

 the odoriferous emanations are intense they may be perceived by the 

 .surfaces of the body that are covered with thin chitin and provided 

 with terminal excitable nerves. 



Plateau (1886) used four Blatta (cockroaches), two with their 

 maxillary and labial palpi cut off and their antennae left intact and 

 the other two with the antenn?e cut ofif and the palpi left intact. These 

 four insects were put into a large circular dish 8 inches in diameter. 

 This vessel contained a bed of fine sand and in the center there was 

 a round pasteboard box 2 inches in diameter and 2 inches high. Food 

 was put into this box, and these insects were observed each day for a 

 month. Each day he saw one or two Blatta eating the food, and in 

 every instance these were the insects with unmutilated antennae, and 

 he concluded that the antenna are the olfactory organs in Blatta. 



Graber ( 1887) repeated Plateau's experiments by using many cock- 

 roaches and declares that it is sufficiently proved that cockroaches 

 deprived of their antennae smell little or none at all, and that the 

 antennas in these insects actually function as olfactory organs. He 

 also says that for cockroaches (and some other insects) it is shown 

 that the olfactory sense lies in the antennae but this is not the case in 

 all insects. 



Dubois (1895) touched the scent glands situated at the tip end of 

 the abdomen of a female moth with a glass rod and then brought this 

 rod, which had no odor perceptible to him, near a male of the same 



