BUTTERFLIES AND MOTHS IN AUTUMN 61 



Gatherings of autumn butterflies are reinforced by two 

 conspicuous species of day-flying moths. The humming-bird 

 hawk moth can be seen all through the summer half of the 

 year ; but it becomes much more abundant at the end of 

 summer and the beginning of autumn, when the year's brood 

 appears before hibernating. It is a very strange and con- 

 spicuous insect, as it hangs, whirring like a humming-bird, at 

 some blossom while it sucks its nectar with its long unrolled 

 proboscis. Its fore wings are smoky grey, and its hind 

 wings rich orange bordered with 

 brown ; it has also large parti- 

 coloured tufts of down about the tail, 

 which it spreads out while hovering 

 so as to help it to float in the air, like 

 the membranes of a flying squirrel. 

 Sometimes it rests on hot brick walls, / 

 and sits fretting its wings together in 

 the sun ; when startled on such a 

 perch, it instantly flashes away in a 

 soaring curve. The second common 

 day-flying moth that haunts flowers 

 is the gamma or silver Y. It is a small moth with long 

 powerful fore wings, marked with a white character re- 

 sembling the Greek and English letters after which it is 

 named. The gamma is also a swift flyer, and occasionally 

 hovers at a flower something in the manner of the humming- 

 bird hawk ; but it is impossible to mistake the two. The 

 hawk moth looks much larger in the air, and its flight is far 

 more buoyant and commanding ; when it hovers at a flower 

 its wings vibrate in a rapid blur. The vapourer moth 

 generally appears in September, though in years when it is 

 abundant it can be seen all through the summer. It is some- 

 times very plentiful in the London parks. The male is con- 



SILVER Y MOTH 



