INSTINCTS APPARENTLY DETRIMENTAL TO THE SPECIES. 2 t 9 



duced as evidence of an instinct detrimental alike to the 

 individual and to the species. But before this conclusion 

 could be reached, several possibilities require to be attended 

 to. In the first place, flame in Nature is an exceedingly rare 

 phenomenon, so that we could scarcely expect that any 

 instinct should have been developed for the express purpose 

 of its avoidance. Therefore, if the general economy of night- 

 flying insects is such that it is of advantage to approach and 

 examine shining objects, there would be nothing anomalous 

 in their failing to distinguish between flame and other 

 shining objects — such as white flowers or, in the case of 

 moths, pale coloured members of the opposite sex. But as 

 the instinct of flying into flame is of such general occurrence 

 among many species of insects, I think we certainly cannot 

 attribute all the cases of it to a mistaking of flame for some 

 other shining object ; to meet all the cases some still more 

 general explanation is required, and this, I think, is afforded 

 by considering other and analogous cases. Thus many 

 species of birds display an exactly similar propensity, as is 

 proved by the experience of lighthouse keepers ; and, accord- 

 ing to Professor A. Newton, some species of birds are more 

 readily attracted by light than others.* Here there can be 

 no question about a possible mistaking of flame for white 

 flowers, &c., and therefore the habit must be set down to 

 mere curiosit)^ or desire to examine a new and striking 

 object ; and that the same explanation may be given in the 

 case of insects seems not improbable, seeing that it must 

 certainly be resorted to in the case of flsh, which, as I pointed 

 out in '•' Animal Intelligence," are likewise attracted by the 

 light of lanterns, &c. ; and the psychology of a fish is not 

 much, if at all, in advance of that of many insects. 



Thus, in any case, it seems certain that we have no reason 

 to regard the propensity in question as an expression of any 

 instinct specially formed with reference to flame, and this is 

 really the only point with wliich we are directly concerned. 

 But, as the subject is in itself an interesting one, I shall here 

 add a few remarks with reference to other aspects of it. 



Among Mr. Darwin's MSS I find the following note, 

 which, however, is not in his hand-writing. 



" Query. Why do moths and certain gnats fly into candles, 

 and why are they not all on their way to the moon — at least 



* YarrelVs Brit. Birds, 4th ed., II, 235 



