264 THE HUMBLE-BEE : 
of the comb; this scent may be perceived by 
smelling the bees that have been collected in the 
glass jar when a nest is taken, after they have been 
allowed to quiet down. But if these bees are 
irritated, by being breathed upon, for instance, 
another smell, namely that of sting-poison, is pro- 
duced. That the humble-bees themselves are 
highly sensitive to these different smells I have had 
many striking proofs. Once I saw a /ucorum queen 
enter one of my domiciles in which a /apzdarius 
queen had collected a lump of pollen and deposited 
her first eggs. Although the /agzdarius was not 
at home, the Zwcorum queen bundled out of the nest 
in great confusion, whether disgusted or terrified 
I cannot say. 
This antipathy to the smell of a strange species 
and its brood is probably the chief obstacle in the 
way of getting different species to fraternise in a 
nest. The introduction of cocoons containing 
workers near emergence from a sy/varum nest into a 
strong /afidarius nest produced a great commotion 
which did not completely subside for a day or two, 
and when the sy/varum workers crept out they 
were all killed. A small pellet of vudevatus wax 
placed in the same colony threw it into an uproar. 
On the other hand several remarkable associa- 
tions between strange species occurred. A dwarfed 
lapidarius worker in some way got out of one of my 
lapidarius nests and entered a nest of ¢errestris in 
which a queen and two workers were confined. 
She immediately became one of the family, paying 
