27 6 THE HUMBLE-BEE 



nfined terrestris 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 latreillellus 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 Psithyrus rupestris in Nests of 

 Bombus lapidarius. On June 13 I put a rupestris queen 

 into a lapidarius nest containing 14 workers and much 

 brood. The lapidarius 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 Psithyrus, emboldened by 

 her fear, tried to sting her as she passed her. I afterwards 

 removed the Psithyrus, but the lapidarius queen did not 

 dare re-enter the nest, and she fell into a drowsy state in 

 the vestibule. 



A lapidarius nest containing a rupestris queen was 

 kept under observation for three weeks, from July 2 to 

 July 23, 191 2. On July 2, when the Psithyrus was intro- 

 duced, the nest contained about 30 workers and a great 

 deal of brood, and she killed the lapidarius queen on the 

 same day. The Psithyrus 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 



,s, numbering 23, were laid in six minutes. During 

 ovipositing she always crossed her hind metatarsi behind 



