36 • 
insects and in the ligula and the maxillae of bees and wasps are con- 
ceded by the authorities to be gustatory. 
Smell. — That insects possess the power of smell is a matter of com- 
mon observation and has been experimentally proved. The many 
experiments of Luboock upon ants left no doubt in his mind that the 
sense of smell is highly developed in them. Indeed, it is the acuteness 
of the sense of smell which attracts many insects so unerringly to 
given objects and which has led many persons to believe them sharp- 
sighted. Moreover, the innumerable glands and special organs for 
secreting odors furnish the strongest indirect proof of the same fact. 
Some of these, of which the osmaterium in Papilionid larvae and the 
eversible glands in Parorgyia are conspicuous examples, are intended 
for protection against inimical insects or other animals; while others, 
possessed by one only of the sexes, are obviously intended to please or 
attract. A notable development of this kind is seen in the large gland 
on the hind legs of the males of some species of Hepialus, the gland 
being a modification of the tibia and sometimes involving the abortion 
of the tarsus, as in the European H. liectm L. and our own H. behrensi 
Stretch. The possession of odoriferous glands, in other words, implies 
the possession of olfactory organs. Yet there is among insects no one 
specialized olfactory organ as among vertebrates; for while there is con- 
clusive proof that this sense rests in the antennae with many insects, 
especially among Lepidoptera, there is good evidence that in some 
Hymenoptera it is localized in an ampulla at the base of the tongue, 
while Graber gives reasons for believing that in certain Orthoptera 
(Blattidse) it is located in the anal cerci and the palpi. 
Hearing. — In regard to the sense of hearing the most casual experi- 
mentation will show (and general experience confirms it) that most 
insects, while keenly alive to the slightest movements or vibrations, 
are for the most part deaf to the sounds which affect us. That they 
have a sense of sound is equally certain, but its range is very differ- 
ent from ours. A sensitive flame arranged for Lubbock by the late 
Prof. Tyndall gave no response from ants, and a sensitive microphone 
arranged for him by Prof. Bell gave record of no other sound than the 
patter of feet in walking. But the most sensitive tests we can experi- 
mentally apply may be, and doubtless are, too gross to adjust them- 
selves to the finer sensibilities of such minute, active, and nervous 
creatures. There can be no question that insects not only produce 
sounds, but receive the impression of sounds entirely beyond our own 
range of perception, or, as Lubbock puts it, that "we can no more 
form an idea of than we should have been able to conceive red or 
green if the human race had been blind. The human ear is sensitive 
to vibrations reaching at the outside to 38,000 in a second. The sen- 
sation of red is produced when 470 millions of millions of vibrations 
enter the eye in a similar time; but between these two numbers vibra- 
tions produce on us only the sensation of heat. We have no especial 
