28 The Structure and Special Physiology of Insects 
various communities the members of their own community. Miss Fielde’s 
experiments show that the recognition of ants by each other depends on the 
existence of a sense of smell of remarkable differentiative capacity. The 
odors of the nest, of the species, of the female parent, and of the individ¬ 
ual are all distinct and perceivable by the smelling-organs, situated on 
distinct particular antennal segments. In the insectary at Cornell University 
a few years ago a few females of the beautiful large promethea moth were 
put into a covered box which was kept inside of the insectary building. 
No males of this moth species had been seen about the insectary nor in 
its immediate vicin¬ 
ity for several days, 
although they had 
been specially sought 
for by collectors. 
Yet in a few T hours 
after the female 
moths were first con¬ 
fined nearly fifty 
male prometheas 
were fluttering about 
outside over the glass 
roof of the insectary. 
They could not see 
the females, but un¬ 
doubtedly discovered 
them by the sense of 
smell. These pro¬ 
methea moths have 
elaborately branched 
or feathered anten¬ 
nae, affording area 
for very many smell- 
ing-pits. 
Mayer’s experiments with promethea also reveal the high specialization 
of the sense of smell. This investigator carried 450 promethea cocoons 
from Massachusetts to the Florida keys. Here on separated small 
islands the moths issued from the cocoons, hundreds of miles south of their 
natural habitat. This isolation insured that no other individuals than 
those controlled by the experimenter could confuse the observations. 
Female moths were confined in glass jars with the mouth closed by 
netting. Other females were confined in smaller glass jars turned upside 
down and the mouth buried in sand. Males being released at various 
Fig. 55.—Auditory organ of a locust, Melanoplus sp. The 
large clear part in the center of the figure is the thin tym¬ 
panum with the auditory vesicle (small, black, pear-shaped 
spot) and auditory ganglion (at left of vesicle and connected 
with it by a nerve) on its inner surface. (Photomicrograph 
by George O. Mitchell; greatly magnified.) 
