326 THE SPHINGIDA OF SINGAPORE. 
Their flight is strong and swift, and the movement of the 
wings very rapid giving rise toa humming noise, which in 
the case of the humming bird hawks has given them their 
popular name. 
As would be expected in swift-flying insects, their wings 
are long, narrow and pointed, with a strong rigid costa, and 
their bodies more or less fusiform, which renders their pas- 
sage through the air more easy. 
In all the hawks the proboscis is of great length, in order to 
enable them to reach the juice at the bottom of the long tubes 
of the flowers they frequent. In the green elephant (Pergesa 
acteus) this organ attains to 24 times the length of the body. 
Each species has one or more favourite flowers which it 
frequents. 
From sundown till dark—the humming birds appearing half 
an hour earlier—they may be seen darting from flower to flow- 
er and ever and anon pausing motionless but for the swift 
movement of the wings, which appear but as a shadow on 
each side before a flower from which, by means of their long 
slender proboscis they are drinking the nectar. They scarce- 
ly ever touch the flowers with their feet and never alight 
on them, but depend entirely on their wings for support. As 
soon as they have exhausted the supply of honey in one flow- 
er off they dart to another, where they repeat the same pro- 
cess. 
Sphinx convolvult has been known to come into a hole 
room and go round to the flowers in vases drinking the 
honey. 
Several species come to light and one or two are rarely taken 
any other way, for instance, the death’s head and oleander. 
The latter has been taken in considerable numbers at the 
beam of a powerful electric light which was being worked in 
the neighbourhood of some jungle. 
These moths probably play an important part in the 
fertilization of the plants they frequent. 
Whether they remain on the wing all night is difficult to 
say. They appear to leave the flower-beds soon after dark, 
as they fill themselves very rapidly with honey. I have, how- 
