22 Transactions. — Miscellaneous. 



tennas are more conveniently situated for the perception of 

 more distant objects. The remarkable power possessed by 

 the males of many species of moths which enables them to dis- 

 cover a newly emerged female of the same species, even when 

 enclosed in a box situated perhaps a considerable distance 

 from the insect's natural haunts, is well known to collectors ; 

 and its truth is sufficiently proved by the very much higher 

 prices charged by dealers in entomological specimens for the 

 female specimens of all such species. This faculty of finding 

 the female at a distance is in all probability resident in the 

 antennas of the male, which are always very amply pectinated 

 in all those species possessing abilities of the kind. It is not, 

 however, by any means certain that the sense involved is that 

 of scent only. In the mosquitoes, at any rate, it has been 

 practically proved that the ability to discover the location of 

 the female is due to a sense nearly akin to that of hearing, 

 and that this sense is situated in the extensive pectinations of 

 the antennae possessed by the male of that insect. 



In connection with this subject the following ingenious 

 experiment made by Mayer is of interest : He fastened a 

 male mosquito down on a glass slide, and then sounded a 

 series of tuning-forks. With an Ut 4 fork of 512 vibrations per 

 second he found that some of the hairs were thrown into 

 vigorous movement, while others remained nearly stationary. 

 The lower (Ut 3 ) and higher (Ut 5 ) harmonics of Ut 4 also caused 

 more vibration than any intermediate notes. These hairs, 

 then, are specially tuned so as to respond to vibrations num- 

 bering 512 per second. Other hairs vibrated to other notes, 

 extending through the middle and next higher octave of the 

 piano. Mayer then made large wooden models of these hairs, 

 and, on counting the number of vibrations they made when 

 they were clamped at one end and then drawn on one side, 

 he found that it " coincided with the ratio existing between 

 the numbers of vibrations of the forks to which co-vibrated 

 the fibrils." It is interesting that the hum of the female gnat 

 corresponds nearly to this note, and would consequently set 

 the hairs in vibration. Moreover, those auditory hairs are 

 most affected which are at right angles to the direction from 

 which the sound comes. Hence, from the position of the 

 antennas and the hairs, a sound will act most intensely if it is 

 directly in front of the head. Suppose, then, a male gnat 

 hears the hum of a female at some little distance. Perhaps 

 the sound affects one antenna more than the other. He 

 turns his head until the two antennas are equally affected, 

 and is thus able to direct his flight straight towards the 

 female. 



The auditory organs of insects, then, are situated, in dif- 

 ferent insects, in different parts of the body ; and there is 



