50 



came to maturity in that year. The following year the queen 

 began to lay late in May, when there were already some pupio 

 in the nest. These pupœ began to hatch in July, and proved 

 to be L. niger workers, so they must have been the oñspring of 

 the L. niger workers, as in the 1896 experiment. Nothing but 

 L. niger workers came to maturity during the year, so the eggs, 

 or larvae of the queen must have been devoured as before. 



In 1911 the pupee began to hatch on July nth, when four 

 callow L. umhratus workers were observed. Numbers came 

 to maturity during the summer, and were unmolested by the 

 L. niger workers, and by the autumn the colony contained about 

 equal numbers of L. umhratus and L. niger. 



This summer the first callows hatched in July, and, judging 

 from the number of pupie, by the end of the year the L. umbratus 

 workers will outnumber the L. niger workers by about two to 

 one. 



The L. umhratus of this and the 1896 colonies have all been 

 of uniform and small size, and those now in the former nest 

 have more the habits of L. niger than of L. umhratus. The 

 latter do not pay much attention to the queen, who is generally 

 surrounded by a bevy of L. niger workers. 



Lord AvEBURY has found that workers of L. niger will live 

 seven years or more, and some of those in this colony must be 

 four or more years old : a colony of L. umhratus, therefore^ 

 founded by adoption in this manner, must take more than five 

 years to become exclusively L. umhratus. 



Crawley, in September 1910, experimented with artificially 

 deälated females of L. umhratus and two queenless colonies 

 of L. niger, and found the females readily accepted. 



The act of removing the wings, however, was far from arousing 

 the instincts possessed by a fertilised female, as is the case with 

 females of F. rufa and jF. sanguinea, and these females, though 

 they lived for several months in the L. niger nests, were restless 

 and tried to escape, and when the entrance to one of the nests 

 was left open, one escaped and was lost. 



Judging from these experiments, which were made with 

 populous colonies of L. niger, and not with nests containing a. 

 few workers, the L. umhratus femdile is adopted in the true sense 

 of the word, is willingly received and even escorted into the 



