E. M. CAMPBELL-ON INSTINCT. 
133 
menon.” The occurrence of an unprotected flame even in our 
country cannot have been so frequent as to lead us to expect that 
the habit of its avoidance could already have been developed. We 
can however recognise in the case of insects the material on which, 
natural selection could act, or may be now acting. We know that 
all the species of moths, and all the individuals of any particular 
species, are not equally attracted by flame. Some few house-flies 
and blue-bottles will beset a candle, especially in autumn, while 
others pass by unheedingly. The collector’s lamp is not very 
successful with the Bombyces, while the white ermine moths will 
flock to it. Again, during the revision of this paper for the press, 
there has been in my room for three days a red underwing ( Calocala 
nupta) which has not performed any gyrations round my reading- 
lamp, although at other times I have often found charred remains 
of individuals of this species. Lights in granaries and cellars do 
not reduce to an appreciable degree the number of small moths 
which occasionally abound in such places. Many are destroyed, 
but sufficient numbers are left to be an inordinate pest. 
Amongst Darwin’s MSS. was found the following pertinent 
query:*—“Why do moths and certain gnats fly into candles, 
and why are they not all on their way to the moon—at least 
when the moon is on the horizon?” Romanes suggests in answer 
to this question that insects fly into flame just as birds fly 
against lighthouses, “out of mere curiosity or a desire to examine 
a new and striking object,”! an d “ as moon is a familiar 
object, the insects regard it as a matter of course, and so have 
no desire to examine it.”J This view may be correct, but any 
explanation of these occurrences must be hypothetical. There 
is no evidence that curiosity is manifested by any individual not 
included in the Yertebrata, or at any rate by the Lepidoptera 
and Remocera. Further, the action of a moth repeatedly knocking 
its head violently against the glass shade of a gas lamp, or of a 
bird in striking a lighthouse, is totally different from that of the 
tentative caution which characterises inquiry throughout the animal 
kingdom. Curiosity might, it is true, lead the moth to the lamp, 
but its rapid and violent gyrations must be due to some other cause. 
It should be borne in mind during the following explanations as to 
these flame-seeking habits that few of the individuals which have 
had any experience of flame live to apply it, and that the vast 
majority of animals can only interpret its appearance by a re¬ 
semblance to something which is related to their habits. In the 
case of birds flying against lighthouses, I would suggest that in 
the history of their own race and within their own experience, they 
must have been in a dark recess, such as a well-shaded nook in a 
forest, or a hole in a rock or tree. Row the light of the sun as it 
strikes upon the egress of such places, when viewed from within, 
has even to ourselves a very close resemblance to a flame, and it is 
through such brilliant openings that birds have been accustomed to 
* ‘ Mental Evolution in Animals,’ p. 279. f lb., p. 279. J lb., p. 280. 
