22 ELEMENTS OF EJJTOMOLOGY. 



Fissile, with the knol) divided longitiadinally into laminae or plates; 

 Fcrfoliatc, having tlie knoh divided horizontalh'; 

 Pectinate, having a longitudinal series ol" hairs or processes project- 

 ing from them in form oi" a comb ; 



Furcate, or tbrivcd, luiving the last joint divided into parts. 

 Nothing has been the source of greater speculation tlian the %ise of 

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

 exhibited in their structm-e, 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 tremulous vibratory motion, anxiously searching into every cre- 

 vice ; while those of the carrion-tly scarcely appear endowed with ilexi- 

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

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



Bonnet seems to think the antenna." the orsran of smell. "Different 

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

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

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

 the antennas are ihe olfactory organ, lie made an opening an inch wide 

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

 that a close covering could be applied. An aperture was made in this 

 covering, through which either the whole head, or the antenna' only 

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

 filled with penetrating odours, vapours, or heated air; but neillier the 

 fumes of sidphur nor burnt feathers produced the smallest effect on 

 butterflies, bees, or beetles, whose antenncC were exposed to them. He 

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

 what else," says he, " is the sense of the particles inspired than smell- 

 ing.?" 



Bonsdorf, in discussing whether the antenna" may be the seat of 

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

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

 loud noise being suddenly made, and fell to the grc^id, 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- 

 tennte on any sudden noise, and many Colcoptera to depress them ; 

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

 Spiders also, which want antennoe, are extremely sensible of sound. 

 Lehmann relates that, on observing 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 u})wards; he was 

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

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

 vuilil familiuii^ied with the sound or conquered by tlie object of its 



