Quadrupeds. 953 



some towery spot, seeking good lodgings for the winter in company with its fellows: 

 such a habit would also account for the vast congregations of bats that have at various 

 times been broken in upon at Oxford and elsewhere. Its flight is always strong, but 

 varies remarkably at different times, no doubt influenced, like that of the swallow, by 

 the casual range of its prey ; at one time it may be seen flying away, straight and 

 swift, at a great height hi the air, no more to appear that evening ; at another it will be 

 performing a great circle, returning perhaps once in five or ten minutes ; or it maybe 

 flying low (and then I think silently) along the streets of a town : again it is wheeling 

 round tall elms, in company with others of its own species, at the time of year when 

 the small hairy cockchafer (Melolontha (?) solstitialis) is swarming about them. Then 

 its powers are seen to perfection, and the great advantage over the feathered tribes 

 that it derives from the mammalian articulation of its wings is beautifully evident. 

 It may easily be brought within shot, for if a stone be thrown just before it, it will 

 follow it nearly to the ground ; no doubt thinking it is an insect, and so pursuing it 

 as prey, and not as an object of curiosity, or as a subject for tyranny, as the Purple 

 Emperor is said to do under similar circumstances. Its latest are by no means its 

 lowest flights ; even in November I have observed it at such a height, that I could 

 hardly have seen it, had not my eye been directed to it by its cry. This is the cricket- 

 like chirp which it always makes with incessant repetition when flying high ; whether 

 it also always makes it when flying low I cannot recollect, but I rather think not : it 

 calls my attention to the animal when it is within a hundred yards or so, frequently 

 giving me the first intimation of its presence : it is so readily distinguished by its 

 peculiar cadence from the chirp of other bats, that however dark the evening, it gives 

 me certain indications of the Noctule. I have often greatly astonished my compa- 

 nions, by announcing the approach of a bat, even before it came in sight : for it is a 

 remarkable fact, that most, or at all events many people are unable to hear this and 

 similar highly stridulous sounds, as for instance, that sometimes emitted by the open- 

 ing of a pair of scissars. It is also worthy of notice, that for those who hear them for 

 the first time, it is difficult to form the least idea from what direction they come ; but 

 I believe the same happens with other kinds of sounds that are heard for the first 

 time, and, if I mistake not, it is said to be a fact, that the intuitive perception we 

 have of the direction in which sounds come, is only acquired by practice and observa- 

 tion. However, this subject of the different capabilities of ears is a highly interesting 

 one, for as we find that most men are quite unable to detect certain sounds which are 

 distinctly heard by others from a great distance, and above almost every other sound, 

 so we are led to understand how there may be forcible sounds which are inaudible to 

 any of mankind, and which nevertheless may be heard at vast distances by the species 

 of creature which excited them- In the few insects that I know to utter any sound, 

 it is a stridulous one. I am not aware whether or not it is yet understood by what 

 means the Death's-head Sphinx raises its cry ; if it were, perhaps, similar, facilities 

 might be discovered in other insects, so as to satisfy us they do utter sounds, though 

 they are too shrill and subtle for our ears. May not the use of the tragus, or inner 

 ear of bats be to catch such sounds as these, as the exfoliated nose of some species is 

 to detect the rarest essences of smells ? For whilst there are some insects of which we 

 know how the males are guided to the females, there are still more of whose means of 

 finding each other we cannot even guess with any degree of certainty : of the first we 

 know the glow-worm and many others use light as a nocturnal beacon. Some exude 

 peculiar odours, and some we know to make various kinds of sounds. Of the second, 



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