524 
LEPIDOPTERA. 
going to get. This subject is dealt with in two notable papers (Trans. 
Ent. Soc., London, 1902, p. 287, and Proc. Zool. Soc., London, 1902, II, 
p. 230), and with a vast wealth of confusing nomenclature in Beddard’s 
“Colour of Animals.” The sincere student with a profound faith in 
human nature may be cautioned against accepting any conclusions or 
facts not based on observation of insects in their natural conditions ; 
the search for explanations of insect colouring has almost rendered the 
whole subject ridiculous since conclusions have been drawn from 
Museum specimens, which have no relation to the lives of insects ; but 
it does not require much field observation to convince the student that 
mimicry of this kind is a real feature of insect life. 
In our second division we have included such insects as make 
special efforts to conceal themselves. Possibly this applies to every insect, 
except such as are protected by devices coming under other heads. A 
great number of caterpillars, for instance, feed at night only ; so do most 
moths ; Perlidce Ephemeridce and some other Neuroptera appear only at 
night, when most birds are asleep and their chance of escaping is greater. 
These and other insects must also protect themselves during the day; 
a green caterpillar sitting motionless among green leaves does probably 
escape the observation of predatory birds, wasps, etc., more often than 
one not so coloured ; the combination of such colouring with the habit 
of resting motionless by day is very common indeed, and when one 
realizes how constantly birds, wasps and stinging predators are search¬ 
ing for caterpillars, one can believe that the colouring and attitude are 
essential to the continuance of that species. We need not dilate upon 
this ; any observer of nature can see it for himself ; moths are extremely 
often found sitting motionless on bark, coloured like bark and really 
quite indistinguishable ; a great variety of insects are of this colour ; 
more are leaf-like or are sufficiently green to be invisible among green 
leaves; the grass mantid is a splendid example of an insect that is 
invisible in grass; throughout the pages of this book we note examples, 
and they are not more fully illustrated for the simple reason that in a 
truthful illustration the insect would not be seen, and if the illustration 
accents the insect enough for it to be seen, it is not truthful. 
Finally there are insects that are supposed to escape by startling or 
frightening their enemies; we deal with this subject very cautiously 
because what startles us may not really startle a bird or a toad or a preda¬ 
ceous beetle at all; in this subject again, conclusions have been freely 
drawn from insufficient data. The resemblance to a snake or to some 
weird large-eyed creature is one that is often quoted, for instance, in 
sphingid larvae ; the apex of the wing of the atlas moth is said to look 
like a cobra’s head ; the full grown larva of Papilio demoleus is said to be 
snake-like ; the caterpillar of the notodontid, Stauropus alternus. looks 
like nothing else and is supposed to frighten its foes; the large sphingid 
caterpillar in the Himalayas which waggles its head backwards and for¬ 
wards, at the same time hissing, may frighten birds off : the caterpillars 
