22 ELEMENTS OF EKTOMOLOGY/ 



Fissile, with the knob divided longitudinally into laminae or plates; 



Ferfoliate, having the knob divided horizontally ; 



Pectinate, having a longitudinal series of hairs or processes project- 

 ing from them in form of a comb ; 



Furcate, or forked, having the last joint divided into parts. 



Nothing has been the source of greater speculation than the iise of 

 the untentuc : nor is this surprising, considering the variety constantly 

 exhibited in their structure, occupation, and appearance. Some insects 

 seem to keep them in continual employment ; in others they are pre- 

 served in a quiescent state. Those of the ichneumon show an inces- 

 sant ti-emulous vibratory motion, anxiously searching into every cre- 

 vice; while those of the carrion-fly scarcely appear endowed with flexi- 

 bility. They have successively been considered as the organs of hear- 

 ing, feeling, smell, and taste, or of an unknown and indetinite sense. 



Bonnet seems to think the antennae the organ of smell. "Difterent 



insects," he observes, " have an exquisite sense of smelling, the organ 



of which is yet undiscovered. May it not reside in the antenna ? " 



Lehmann, from the result of experiments on this subject, denies that 



the antennas are the olfactory organ. He made an opening an inch wide 



in the side of a glass vessel, and surrounded the edge with wax, so 



that a close covering could i)e applied. An aperture was made in this 



covering, through which either the whole head, or the antennae only 



of an insect could be introduced. By means of a tube the glass was 



filled with penetrating odours, vapours, or heated air; but neither the 



fumes of sulphur nor burnt feathers produced the smallest effect on 



buttei-flies, bees, or beetles, whose antenna? were exposed to them. lie 



judges that the olfactory organ must be sought in the spiracula; " for 



,,rV.Qf nU^ " ^"'''' ^^" " '"^ *^'^ concA of the particles inspired than smell- 

 ing ? " ^ 



Bonsdorf, in discussing whether the antenna; may be the scat of 

 hearing, mentions an experiment where a species of beetle, Avhose pe- 

 culiar property it is to fold in the antenna- when alarmed, did so on a 

 loud noise being suddenly made, and fell to the ground, according to 

 the nature of the species. But, notwithstanding "that the animal pre- 

 viously reposed in a tranquil state, his experiment cannot be consi- 

 dered altogether conclusive. Butterflies are seen to erect their an- 

 tenna? on any sudden noise, and many Coleoptera to depress them ; 

 which may equally arise from the sudden shock or vibration of the air. 

 Spiders also, which want antenna?, are extremely sensible of sound. 

 Lehmann relates that, on obserA'ing one descend from the roof by its 

 thread in quest of a female, while he was reading, he began to read 

 aloud: the animal, alarmed at the noise, retreated upwards; he was 

 silent, and it returned; on again reading aloud, it testified alarm and 

 ascended its thread; nor was its apprehension of danger dispelled, 

 until familiarized with the sound ur conquered by the" object of its 



