PAS Ore RT ae OF AORE See NN L eR eS nee Ba Page a or UES 
i 
es: 
A 
aS 
AUDITORY APPARATUS OF THE MOSQUITO. 581 
with an auditory nerve which arises from the third thoracic gan- 
glion, forms a ganglion on the tympanum, and terminates in the 
immediate neighborhood of the labyrinth by a collection of cunei- 
form, staff-like bodies with very finely-pointed extremities (primi- 
tive nerve-fibres ?), which .are surrounded by loosely-aggregated, 
ganglionic globules. (This organ has been taken for a soniferous 
apparatus by Latreille. J. Miller was the first who fortunately 
conceived that with Gryllus hieroglyphus this was an auditory 
organ. He gave, however, the interpretation only as hypothet- 
ical; but I have placed it beyond all doubt by careful researches 
made on Gomphoceros, Oedipoda, Podisma, Caloptenus and Trux- 
alis.”) 
“The Locustidæ and Achetidæ have a similar organ, situated 
in the fore-legs directly below the coxo-tibial articulation. With 
a part of the Locustidæ (Meconema, Barbitistes, Phancroptera, 
Phylloptera), there is on each side of this point a fossa, while with 
another portion of this family there are, at this same place, two 
more or less spacious cavities (auditory capsules) provided with 
orifices opening forward. These fossæ and these cavities have 
each, on their internal surface, a long-oval tympanum. The prin- 
cipal trachean trunk of the leg passes between two tympanums, 
and dilates, at this point, into a vesicle whose upper extremity is 
in connection with a ganglion of the auditory nerve. This last 
arises from the first thoracic ganglion, and accompanies the prin- 
cipal nerve of the leg. From this ganglion in question passes off 
a band of nervous substance, which stretches along the slightly 
excavated anterior side of the trachean vesicle. Upon this band 
is situated a row of transparent vesicles containing the same kind 
of cuneiform, staff-like bodies, mentioned as occurring with the 
Acridi The two large trachean trunks of the fore-legs open 
by two wide, infundibuliform orifices on the posterior border of 
the prothorax, so that here, as with the Acrididæ, a part of this 
chean apparatus may be compared to a Tuba Eustachii. With 
the Achetide, there is, on the external side of the tibia of the 
fore-legs, an orifice closed by a white, silvery membrane (tympa- 
num), behind which is an guditory organ like that just described. 
(With Acheta achatina and italica, there is a tympanum of the 
Same size, on the internal surface of the legs in question ; but it 
. Scarcely observable with Acheta sylvestris, A. domestica and A. 
campestris. ” 
