Humble-Bees and other Matters. 157 
it had been stung to death, it had been dragged 
out and left there as a warning to others with like 
felonious intentions. 
There is one striking difference between the two 
species. The yellow bee is inodorous ; the black 
bee, when angry and attacking, emits an exceed- 
ingly powerful odour : curiously enough, this smell 
is identical in character with that made when angry 
by all the wasps of the South American genus 
Pepris — dark blue wasps with red wings. This 
odour at first produces a stinging sensation on the 
nerve of .smell, but when inhaled in large measure 
becomes vory nauseating. On one occasion, while 
I was opening a nest, several of the bees buzzing 
round my head and thrusting their stings through 
the veil I wore for protection, gave out so pungent 
a smell that I found it unendurable, and was com- 
pelled to retreat. 
It seems strange that a species armed with a 
venomous sting and possessing the fierce courage 
of the humble-bee should also have this repulsive 
odour for a protection. It is, in fact, as incongruous 
as it would be were our soldiers provided with 
guns and swords first, and after with phials of 
assafoetida to be uncorked in the face of an enemy. 
■ Why, or how, animals came to be possessed of the 
power of emitting pestiferous odours is a mystery ; 
we only see that natural selection has, in some 
instances, chiefly among insects, taken advantage 
of it to furnish some of the weaker, more unpro- 
tected species with a means of escape from their 
enemies. The most striking example I know is that 
