Occasional Notes. 169 
or eighth segment, they are of equal thickness with the 
hinder parts. Into these large segments, the anterior 
parts are more or less retractile, giving the appearance 
of a more or less broadened and thickened, but quite 
shortened, snout. At the broadest part of this anterior 
portion, two large strikingly eye-like areas are situated, 
which, when the anterior segments are retracted, give 
every appearance of being the true eyes of a particularly 
viper-like object. The resemblance of this caterpillar 
to a snake, and more particularly to the venomous 
labarria (Trigonocephalus atrox), whose colouring it 
also bears, is sufficiently striking to be the object of 
attention, and when the head of the caterpillar is 
suddenly perceived among the bushes of some tree close 
to one's body, it is sufficiently imitative of the poisonous 
snake to cause one to start back involuntarily. 
This is one of the most striking and perfect cases 
of true mimicry to be met with in the colony, in which 
a harmless form of one group is protected by its resem- 
blance in form and colouring to a poisonous form of 
another group. That this form is so protected can 
hardly be doubted, since the very foes that would seek 
it, are some of the very objects that the form it mimics 
would itself seek as food. Though the caterpillar has 
never been directly observed being eaten by birds, 
one can no more doubt its being palatable to birds when 
it has thus been protectively coloured and formed, than 
one can doubt that the gaudy, black, yellow-banded and 
red-legged caterpillar of the frangipani sphinx moth 
(Pseudo sphinx tetrio) is not palatable, flaunting its 
colours in striking contrast on the bare grey branches or 
across the most green leaves, in the most conspicuous 
x 
