REST DURING DAYLIGHT 
599 
a long hedge of various shrubs. It was very hot, with brilliant sun¬ 
shine (early afternoon). A £ rhamni came coursing along the 
hedge; I could see it approaching from some distance. It did not 
fly very rapidly, and I noticed that it once or twice interrupted its 
onward flight, by staying to flutter about part of the hedge, but it 
did not actually stop. It passed in front of me, and a little further 
on I saw it fluttering about some greenish yellow foliage in the hedge. 
It got among the leaves and did not reappear. ... I slowly 
approached the spot ... it was some little time before I could dis¬ 
cover it, but I was at length rewarded by finding it at rest (fore-wings 
well down between hind-wings) on a leaf which in colour was very 
close to that of the underside of rhamni’s wings. The leaf was 
large and pendant, and the outline of the resting butterfly scarcely 
showed against it.” 
Since then I have not added to my experience in this matter, but 
am thoroughly convinced of the reality of the habit. 
In bringing this part of my subject to a close I venture to make 
a remark which has a wide bearing on the whole question of cryptic 
and mimetic resemblances. 
Butterflies are most numerous and varied within the tropics. In 
the tropics the length of daylight varies much less than in temperate 
zones, and is many hours shorter than in the temperate summer. 
At the equator the sun is above the horizon for twelve hours every 
day; at the tropics the sun is above the horizon from a minimum of 
ten and a half hours to a maximum of thirteen and a half hours. 
But although the sun is visible for these long periods, not so the 
butterflies. Yery few comparatively are to be seen on the move 
before 9 a.m., and few after 3 p.m. 
Now my point is that tropical birds, lizards, and other insecti¬ 
vorous animals have some six to eight hours of full daylight in 
which to hunt butterflies, when the latter are more or less at rest. 
This is a fact not usually allowed for in the discussion of questions of 
protective resemblances or mimicry, but it emphasizes the need for 
concealment. 
To those whose tastes lie in that direction, few occupations are 
more delightful than that of the field-naturalist; yet if he, or she, 
is to advance our knowledge there are certain requisites :—patience, 
industry, and method. The successful butterfly hunter is by no 
means the idle and frivolous person that many take him to be: the 
