EFFICIENT POLLINATORS 97 
the Convolvulus Hawk-moth measures 65 to 80 milli- 
metres (24 to 3} inches), and some of the Tropi- 
cal allies of this moth have probosces twice or 
even three times that length. These species feed on 
the nectar of flowers with tubular corollz of corre- 
sponding dimensions. Most of the Hawk-moths feed 
only at dusk, and as the time is short they take advan- 
tage of their powers of rapid flight to visit (and inci- 
dentally to pollinate) a very large number of flowers 
in a short period. Moreover, in common with most 
of the more specialized flower-feeding insects, they 
do not visit the flowers of different species indis- 
criminately, but dash to blossom after blossom of 
whatever single species they have selected. Her- 
mann Miller records watching Humming-bird Hawk- 
moths (Macroglossa stellatarum) at work at the sum- 
mit of the Albula Pass; one visited 106 flowers of 
Viola calcarata in under 4 minutes; another 194 blos- 
soms of the same plant in 6? minutes. 
The day-flying Butterflies display none of this rest- 
less energy. The sunshine is pleasant and the day 
long. They wander aimlessly in their beauty from 
flower to flower, sun themselves on the warm ground, 
or “whirl through the air with the first good com- 
rade that by chance appears.” They are the flowers 
of the air, and our country rambles are made more 
joyous by their careless companionship. 
