On the Organs of Hearing in Insects. 473 



the structure of the external portion inducing us to suppose 

 they can be of service in arresting the undulations of sound ? 

 To each of these important questions I may answer yes, with- 

 out reservation and without a surmise. Observation places 

 the facts on grounds not to be disputed. But to proceed to 

 the proof. 



During the time I was studying the utility of the antenna, 

 whilst walking in the garden between eight and nine o'clock 

 at night, T saw a specimen of Carabus memoralis, (Illiger) 

 in search of food, which consists of worms and small coleop- 

 terous insects, that conceal themselves in the earth, or on its 

 surface under stones &c. For rather more than a quarter of 

 an hour I amused myself with observing its motions on new- 

 ly turned up ground, without being inconvenienced by the 

 interruption of plants or weeds. It walked with the antennas 

 bent forward and somewhat arched, occasionally touching the 

 ground with them in its progress. On reaching a clod of 

 earth they were placed beneath, yet still arched. Could it be 

 feeling for anything ? No ! because, if so, they would have 

 been stretched out rather than arched. When it discovered 

 any worm-holes, the tips merely were inserted, or one of them, 

 and it paused as if listening for prey. I have sometimes seen 

 terrier dogs do the same, when waiting for a rat ! I returned 

 to the house, and taking an insect of the same species from 

 my collection, carefully inspected every joint of the antenna 

 one by one ; then bent them into the same form : I afterwards 

 turned both of them backward, over the thorax, so that the 

 tips met on the suture of the elytra, beyond the scutellum. — 

 Now looking in front I discovered an opening in the lob a. 

 I said in my last, that they were organs of hearing, even if 

 there be no external communication with the atmosphere : — 

 the if vanished; all doubt was removed ; and I perceived that 

 they could hear as plainly as I could myself; — much more so 

 indeed, because the upper part of the antennce has the power 

 of increasing the sound. My exertions were thus rewarded 

 by results that even my most sanguine expectations had not 

 dared to hope for, though I was previously convinced by dis- 

 section that the internal formation required this meatus. I 

 then determined to use this as my first test, as I had in my 

 possession nearly a hundred duplicate specimens on which I 

 could exercise my patience. 



The antennce of this insect are filiform, and their situation 

 pre-ocular. a is the natural size, b magnified. 1 is the lo- 

 ba, 1 ° the scapus : the loba {torulus, Kirby) is not a distinct 

 articulation, but a process of the scapus. Each individual 

 joint also has an insertion, {c) that fits into the cup of the one 



