294) BONSDOUF ON THE ANTENN.fi OF INSECTS. 



made on the antennae by such substances as come in contact with them, 

 I shall now inquire, whether the odorous effluvia of bodies, or whether 

 sounds are perceived by the antennae. The conjecture of the distin- 

 guished C. Clerck, delivered in his inaugural discourse in the year 1764, 

 before the Royal Academy of Sciences at Stockholm, concerning what 

 is remarkable in insects, first maintained, with confidence, that the 

 antennae are organs of smell. He was, he says, led to this, by ob- 

 serving that certain beetles, (Melolontha aurata and M. fasciata.) 

 when alighting on flowers which are grateful to them, open the plates of 

 their antennae in the same way as horses after a hard gallop are 

 observed to expand their nostrils to the cool air. Indeed ! Yet our 

 most acute M. Tobern Bergmann adopted Clerck's opinion, and men- 

 tioned that he himself had often seen the ichneumon jaculator prying 

 with its antennae into the holes which contained the grubs of sphex 

 figuli, as if to smell them out, in the manner pursued by many other 

 animals. This argument, however, has no great weight, although we 

 may, in some measure, give our assent to the fact recorded. We need 

 no more be surprised at seeing beetles incited by rapid motion, at one 

 time open, and at another shut the plates of their antennae, than when 

 we observe horses, or any other animals, when fatigued from labour or 

 swift flight move their ears : nay, even the whole body, in such cases, 

 may be seen to tremble. 



Insects undoubtedly perceive at a distance their prey, and substances 

 agreeable to them by smell, or some other sense ; whence it appears that 

 the effort of smelling is quite unnecessary, in the instance of flowers 

 upon which they may alight. Nor does the history of the ichneumon 

 appear to me sufficient to establish this opinion, since I think it very 

 credible that the presence of grubs living in the bottom of their nest 

 holes can be more probably detected from their rolling and creeping 

 motions, and in a place too so narrow, by the organs of hearing, than by 

 the organs recognising smells applied to the exhalations, especially 

 when in the coldest blooded animals the insipid evaporations of bodies 

 are slower and less frequent. These holes besides are seldom dug to so 

 great a depth, that the antennae extended in their whole length could 

 not reach the grubs ; since I have frequently observed, that they not 

 only thrust in their antennae, but their whole head, and even the half 

 of the trunk into the little holes, so that it seems doubtful whether, iu 

 such cases, the true use of the antennae be any thing more than that 

 of touching. 



Nothing therefore remains but to inquire whether the antcnnse may 



