THE DAY OF THE MOTH 97 



try to penetrate, but the emerging moth can easily push 

 them asunder. 



Day-flying moths include representatives of all the most 

 conspicuous families. The emperor and oak eggar and fox 

 moth represent the cocoon-spinners ; the humming-bird 

 stands for the hawk moths, while the heavy noctuae or owl 

 moths contribute the beautiful yellow underwing, and the 

 light geometers the speckled yellow of the May copses. But 

 the great majority of moths are creatures of dusk and dark 

 ness ; and unlike the day-flying insects 

 of their kind, they prefer a dim to a 

 clear sky. This is probably because 

 overcast nights are warmer than clear 

 ones, when the radiation of the earth's 

 heat is unimpeded by cloud ; and so 

 frail a creature as a moth is naturally 

 averse from cold, even if it shuns the 

 sun. For the same reason, they are 

 scarce in the chilly hours immediately YELLOW UNDERWING 

 before the dawn, and are most abundant 



on the wing from dusk to about midnight. One of the 

 first signs of full spring in April is the appearance of the 

 frail and silvery carpet moths after dusk in the soft night air ; 

 and moths linger late into autumn during soft weather, while 

 a few flimsy yet hardy species are to be seen abroad on mild 

 nights all through the winter. If moths originally became 

 nocturnal creatures in order to escape from birds which fed 

 upon them by day, the precaution has long ceased to be of 

 any service. Bats feed far more persistently on moths by 

 night than any birds do by day ; and the luminous white and 

 yellow tints of such species as the ghost swift and the 

 swallowtail and sulphur moths serve as signals for their own 

 destruction. 



