276 THE HUMBLE-BEE 
egg. (Confined ¢errestrzs queens sometimes eat their own 
or each other’s eggs.) I now separated the two queens— 
they had remained good friends—giving to the one a first 
batch of derhamellus cocoons, soon to hatch, and to the 
other a first batch of datrezlellus cocoons. Each queen 
incubated her brood with the greatest attention. In each 
case the workers that hatched were at first friendly to the 
queen, but later they turned the queen out of the nest 
and laid eggs of their own. 
Behaviour of Queen of Pszthyrus rupestris in Nests of 
Bombus lapidarius—On June 13 I put a rupestris queen 
into a /afidarius nest containing 14 workers and much 
brood. The /apzdariws queen rushed out of the nest and 
ran about the vestibule in great agitation for a long time. 
Occasionally she peeped into the entrance, but she hastily 
withdrew. Once I gently pushed her in, but with extra- 
ordinary strength she forced herself back. I next dropped 
her into the nest, but she dashed wildly about and escaped 
again to the vestibule. The Pszthyrus, emboldened by 
her fear, tried to sting her as she passed her. I afterwards 
removed the Psithyrus, but the /apzdarzus queen did not 
dare re-enter the nest, and she fell into a drowsy state in 
the vestibule. 
A lapidarius nest containing a rupestr7zs queen was 
kept under observation for three weeks, from July 2 to 
July 23,1912. On July 2, when the Pszthyrus was intro- 
duced, the nest contained about 30 workers and a great 
deal of brood, and she killed the /afzdarius queen on the 
same day. The Pszthyrus spent most of her time chasing 
certain workers over the comb, and thus prevented them 
forming cells in which to lay their eggs. Between July 10 
and July 23 she laid a large batch of eggs almost every 
day. She built the egg-cells herself with wax she gathered 
in the nest. The workers became very excited over the 
egg-cell during its construction. She made her cell and 
laid her eggs in it very rapidly. On one occasion the 
eggs, numbering 23, were laid in six minutes. During 
ovipositing she always crossed her hind metatarsi behind 
