100 DR. JOHNSTON, ON THE AUDITORY APPARATUS 



fellow by a transverse fenestrated band, and to which it is 

 joined by a thin elastic membrane. Externally it has a rounded 

 form, but internally it resembles a certain sort of lamp shade 

 with a constriction near its middle ; and between this inner 

 cup and outer globe there exists a space, except at the bottom 

 or proximal end, where both are united. 



The antennce are of nearly equal length in the male and the 

 female. 



In the male the antenna is about 1 • 75 mm. in length, and 

 consists of fourteen joints, twelve short and nearly equal, and 

 two long and equal, terminal ones, the latter measuring 

 (together) • 70 mm. Each of the shorter joints has a fene- 

 strated skeleton with an external investment, and terminates 

 simply posteriorly, but is encircled anteriorly with about forty 

 papillce, upon which are implanted long and stiff hairs, the 

 proximal sets being about 79 mm. and the distal ones 

 • 70 mm. in length ; and it is beset with minute bristles in 

 front of each whorl. 



The two last joints have each a whorl of about twenty short 

 hairs near the base. 



In the female the joints are nearly equal, number but thirteen, 

 and have each a whorl of about a dozen small hairs around 

 the base. Here, as well as in the male, the parts of the an- 

 tenna? enjoy a limited motion upon each other, except the 

 basal joint, which, being fixed, moves with the capsule upon 

 which it is implanted. 



The space between the inner and outer walls of the capsule, 

 which we term confidently the auditory capsule, is filled with 

 a fluid of moderate consistency, opalescent, and containing 

 minute spherical corpuscles, and which probably bears the 

 same relation to the nerve as does the lymph in the scalce of 

 the cochlea of higher animals. The nerve itself, of the antenna, 

 proceeds from the first or cerebral ganglion, advances towards 

 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 

 portions. The central threads continue forwards into the 

 antenna and are lost there ; the peripheral ones, on the con- 

 trai'y, radiate outwaids in every direction, enter the capsular 

 space, and are lodged 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 



