292 



ON THE ANTENNAE OF INSECTS AS ORGANS OF HEARING. 



BY PROFESSOR BONSDORF, OF ABO IN FINLAND *. 



I shall here offer some observations on the use of the antennae of 

 insects, a subject which has been considered difficult of explanation. 

 Nature is always provident of advantages, while much skill is displayed 

 in the construction of instruments for effecting peculiar purposes, 

 though the mode in which these act is not always so obvious, and some- 

 times leads inquirers to form various, or even opposite conclusions. 



Some who are disposed to ascribe every thing to beauty, maintain 

 that the antennae of insects are intended only as an elegant ornament 

 for the head ; while others, from their analogous form and position to 

 the horns of larger animals, imagine that, like these, they are meant to 

 assist insects in attack or defence. The latter forgot that antennae are 

 slender and movable, while horns are strong and firmly fixed. I think 

 this, therefore, is erroneous. Nor am I inclined to think very differently 

 of the explanation which Swammerdam gives, unworthy of his acute 

 and well-practised genius in investigating the economy of insects ; when 

 describing the antennae of bees, he supposes from their very free 

 motion, that they can assist the sight and defend the eyes from ex- 

 ternal injury ; for the entire disposition and action of the antennas pre- 

 vent them from performing the functions of eye-lids and eye-brows, 

 since we perceive them joining the lowest membrane of the eye with 

 such hardness and remarkable tenacity, that without any certain 

 peculiar covering or pother defence, they can preserve their safety 

 without injury. 



But whoever takes delight in examining with care the action of the 

 antennas, will find, that being constantly extended, they are seized 

 with a sudden trembling as if struck by lightning, as often as they are 

 unexpectedly affected by the more violent motions of external objects. 

 He, I say, who has carefully examined all these circumstances, must 

 be justly dissatisfied with the opinion formed by Pliny (book xi. ch. 28), 

 who says, that the little horns extended before the eyes defend them 

 as if covered by a tent, and asserts that a certain sense resides in the 

 antennae, for which purpose these instruments have been constructed. 



* Translated from the Latin, by John Sharp, Esq., Bannockburn, near 

 Stirling. 



