ADDITIONAL NOTES 277 
the cell. Sometimes she constructed two cells in different 
places at the same time, and then, while she laid her eggs 
in the one, the /apzdarius workers, amid much quarrelling, 
would often seize the opportunity to lay their eggs in the 
other. After she had finished guarding her own eggs she 
demolished the cell containing the /apzdarius eggs. She 
was heard to utter the mournful cry (p. 252) on many 
occasions. On July 23 I removed her from the nest for 
four hours to let the workers finish laying eggs in a cell 
which she had begun and they had built up, but when I 
put her back the workers attacked her and stung her to 
death. Although she had laid a batch of eggs only a 
quarter of an hour before she was removed, the workers 
did not molest them. It may be the Pszthyrus kneads 
a distasteful saliva into the wax covering her eggs. 
On another occasion, a strong /apzdarzus nest in which 
a riupestris queen had been reigning for eleven days was 
overturned. The shock of the accident seemed to unnerve 
the Psithyrus, for she wandered aimlessly about the nest, 
and two hours later the workers mobbed her and stung 
her to death. It appears that when the colony is populous 
the rupestris will lose her life unless she maintains con- 
tinuously her rule of repression. 
On July 20 I put a searching rupestris queen into the 
vestibule of a /agzdarius nest containing about 80 workers. 
She passed into the nest without hesitation and imme- 
diately produced an uproar, the workers and their queen 
rushing hither and thither in great excitement. The 
excitement died down in about twenty minutes, and on 
lifting the nest I found the Psz¢hyrus in a dying condition 
with six workers attached to her trying to sting her and 
thirteen dead workers lying around her. A few days later 
I found in this nest a female of the deadly parasitic moth 
Aphomia soceella, and another of the deadly fly Brachycoma 
devia, but the humble-bees paid not the slightest attention 
to them. 
