LETTEES FEOM ALABAMA. 
65 ' 
tlie Four o’Clock^ from tlie singular habit of open- 
ing its flowers just at that hour. During the heat 
of the day they remain closed, the mouth or wide 
part of the corolla being curled inward, and ap- 
pearing shrivelled ; but about four in the afternoon, 
— and I have often been struck with admiration at 
the precision with which the hour is marked,— the 
blossoms begin to unfold, and in the course of a 
quarter of an hour all are widely expanded, and 
remain open all night. They are sweet-smelling, 
and their deep tubes make them a great centre of 
attraction to the large Hawk-moths which choose 
the morning and evening gloaming for their pere- 
grinations ; and it is partly for them that I have 
brought you to this bush. 
We will be patient a moment : — there is one ; I 
hear the humming of his muscular wings: be 
cautious ! now I see him coming round the further 
side of the bush ; we won’t net him yet ; we will 
watch his motions a few minutes, as well as we 
can for the dim twilight. He is suspended on the 
wing, just over the mouth of a flower into which his 
long tongue or sucker is inserted, probing to the very 
bottom, where the nectar lies : his wings are like an 
undefined film on each side, owing to the rapidity 
of their vibration, and by their motion make that 
shrill hum which so instantly discovers his presence. 
Now he is at another flower, having changed -his 
position so quickly that it seems as if done merely 
by a volition, without passing through the inter- 
vening space. He stays three or four seconds at 
each blossom, visiting them in succession, if undis- 
turbed, pretty regularly ; not unerringly, however, 
as he often revisits a flower w^hich he has just 
robbed. He never works in a resting position ; I 
