36 



insects and in the ligula and the raaxilliP. of bees and wasj^s 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 i^roved. The many 

 experiments of Luboock upon ants left no doabt 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 ]arv?e 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 develox)ment 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 R. kectus L. and our own M. hehrensi 

 Stretch. The possession of odoriferous glands, in other words, implies 

 the possession of olfactory organs. Tet 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 tke base of the tongue, 

 while Graber gives reasons for believing that in certain Orthoptera 

 (Blattidoe) it is located in the anal cerci and the palpi. 



Hearing. — In regard to the sense of hearing the most casual experi- 

 mentation will vshow (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 tlame 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 pnts 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 



