384 Prof. A. M. Mayer's Researches in Acoustics. 



relation to the nerve as does the lymph in the scalse of the 

 cochlea of higher animals. The nerve itself of the antenna 

 proceeds from the first or cerebral ganglion, advances toward 

 the pedicle of the capsule in company with the large trachea, 

 which sends its ramifications throughout the entire apparatus; 

 and penetrating the pedicle, its filaments divide into two por- 

 tions. The central threads continue forward into the antenna, 

 and are lost there ; the peripheral ones, on the contrary, radiate 

 outward in every direction, enter the capsular space, and are 

 lodged there for more than half their length in sulci wrought in 

 the inner wall or cup of the capsule. 



" In the female the disposition of parts is observed to be nearly 

 the same, excepting that the capsule is smaller, and that the 

 last distal antennal joint is rudimental. 



" The proboscis does not differ materially in the two sexes ; 

 but the palpi, although consisting in both instances of the same 

 number of pieces, are very unlike. In the female they are ex- 

 tremely short, but in the male attain the length of 2*73 millims., 

 while the proboscis measures but 2*16 millims. They are curved 

 upward at the extremity. 



" . . . . The position of the capsules strikes us as extremely 

 favourable for the performance of the function which we assign 

 to them ; besides which there present themselves in the same 

 light the anatomical arrangement of the capsules, the dispo- 

 sition and lodgment of the nerves, the fitness of the expanded 

 whorls for receiving, and of the jointed antennse fixed by the 

 immovable basal joint for transmitting vibrations created by 

 sonorous undulations. The intracapsular fluid is impressed by 

 the shock, the expanded nerve appreciates the effect of the 

 sound by the quantity of the impression, of the pitch or qua- 

 lity by the consonance of particular whorls of stiff hairs accord- 

 ing to their lengths, and of the direction in which the undula- 

 tions travel by the manner in which they strike upon the 

 antennae or may be made to meet either antenna in consequence 

 of an opposite movement of that part. 



"That the male should be endowed with superior acuteness 

 of the sense of hearing appears from the fact that he must seek 

 the female for sexual union either in the dim twilight or in the 

 dark night, when nothing but her sharp humming noise can 

 serve him as a guide. The necessity for an equal perfection of 

 hearing does not exist in the female ; and accordingly we find 

 that the organs of the one attain a development which the 

 other's never reach. In these views we believe ourselves to be 

 borne out by direct experiment, in connexion with which we may 

 allude to the greater difficulty of catching the male mosquito. 



" In the course of our observations we have arrived at the 



