25 
dragonflies, and all gaily coloured insects, they are either bad 
eating or bad stingers.” On the other hand, the gorgeous tints of 
many snakes which have been assigned by some naturalists to an 
instinct of warning, are, according to Professor Drummond, mainly 
for protection. 
Take, for example, the puff adder, a snake from three to five feet 
long, and disproportionately wide, being sometimes as thick as 
the lower part of the thigh, which looks when under a glass case, 
a most brilliant object, but when seen against the vivid colouring 
of a tropical forest it is scarcely distinguishable from the fallen 
leaves. He continues, ‘‘I was once just throwing myself down 
under a tree to rest, when, stooping to clear the spot, I noticed a 
peculiar pattern amongst the leaves. I started back in horror to 
find a puff adder of the largest size, its thick back only visible, and 
its fangs within a few inches of my face as I stooped. Had it not 
been for the exceptional caution which in African travel becomes a 
habit, I should certainly have sat down upon it, and to sit on a puff 
adder is to sit down for the last time. Tne peculiarity of this 
reptile is that it strikes backward, and the moment any part is 
touched, the head doubles back with inconceivable swiftness, and 
the poison fangs close on their victim.” Thus the colouration of this 
reptile appears to serve rather as protection for itself than as 
warning to its victim. 
Or again, the zebra, whose black and white stripes would seem 
to make it such a conspicuous object, is almost invisible amid the 
dense thickness of a tropical forest, the black and white blending 
together to form an inconspicuous grey. So inconspicuous, says 
Prof. Drummond, that he sometimes found himself-surrounded by 
a vast herd of zebras, of whose presence he was totally unaware 
tall it was betrayed by some movement on their part owing to his 
approach. The spotted leopard, too, conveys the same idea of in- 
distinctness—and along the rivers it is most difficult to ascertain, 
without close inspection, whether the objects lying along their banks 
are fallen trees or the mud-coloured hides of crocodiles and alligators. 
Bui the most striking instances of mimic , both in form and 
colour, are displayed in various insects of the Phasmide and 
Mantide order. These grass-stalk insects live among the tall 
grasses of the forest, the brown-tinged or spotted appearance of 
which they closely imitate ; their texture and colour are like fine 
dried hay, but the colour varies according to the season, changing 
in autumn from a bright red to a deep claret or tawny gold. Prof. 
Drummond’s introduction to one of these insects of the Phasmide 
order can best be told in his own graphic words. He says, ‘‘ I had 
stopped one day among some tall dried grass to mark a reading of 
- the aneroid, when one of the men shouted ‘ Cherombo !’ meaning 
