74 O. E. PLATH. 



meets with the statement that the members of a bumblebee 

 colony are the offspring of one queen, and on this "fact" several 

 of the above-mentioned authors have based far-reaching con- 

 clusions in regard to the genetic constitution of certain species. 

 However the observations of Putnam (1865), Lindhard (1912), 

 Sladen (1912), and Prison (1921) indicate that this is by no 

 means always the case, since queens which have started colonies 

 are often killed and supplanted by others which enter their nest, 

 a fact which is corroborated by my own observations (cf.i922c, 

 19230). Here in the vicinity of Boston, this natural requeening 

 is especially common with Bremus fervidus and Bremus impatiens. 



XVII. NESTS ESTABLISHED BY QUEENLESS WORKERS. 



Wagner (1907) believes that a bumblebee colony which has 

 lost its queen and comb cannot build another nest, and hence is 

 unable to contribute anything toward the next generation. 

 Huber (1802, pp. 288-289), on the other hand, states that bumble- 

 bee workers which have lost both queen and comb are able to 

 start a new nest. 1 



In order to determine which one of these two authors is correct, 

 the following experiments were carried out. On August I, 

 1922, I removed all the comb from a queenless colony of Bremus 

 fervidus which at that time consisted of about 100 workers. 

 The latter at once started to build a new nest and produced a 

 considerable number of males. Two weeks later, the same 

 experiment was performed with a colony of Bremus impatiens 

 consisting of about 300 workers, and this yielded the same result. 

 The accompanying plate shows how the comb of the two colonies 

 looked on August 21, 1922. These experiments prove con- 

 clusively that Wagner's (pp. 116-117, 154-155) contention is 

 incorrect. 



XVIII. THE EFFICIENCY OF BUMBLEBEES. 



Wagner (1907) claims that bumblebees are so inefficient in 

 their work, especially that connected with nest-building, that 

 8/9 of their efforts are wasted. I cannot agree with Wagner (pp. 

 136-154) on this point. While it is true that bumblebees do not 

 produce such populous colonies as certain other Social Hymen- 



1 Wheeler and Taylor (1921) have found that this is also true of social wasps. 



