70 STUDIES IN INSECT LIFE, ETC. 



hairy covering is unusually dense and thick. To 

 distinguish one species from another is no easy 

 task ; to begin with, we have three grades with 

 which to deal the queens, the workers and the 

 males. The last named can be determined by 

 the outline of the armature, which corresponds 

 with the sting in the female, but care must be 

 taken in investigating this, as the parts of this 

 complicated structure are easily displaced and 

 the outline of the whole is thus altered. Much 

 also depends on the colour markings, and here 

 the admirable colour-photographs published by 

 Mr. Sladen in his monograph on the humble-bee 

 cannot fail to be of the greatest use to naturalists. 

 Still the colour is apt to vary within the species, 

 and in systematic work it is quite usual to speak 

 of " light specimens " and " dark specimens." 

 Further, the colour of the hairs is apt to fade with 

 time and, altogether, there are many pitfalls 

 before the systematist in humble-bees. 



If we try to trace the history of the humble-bees' 

 nest we may begin with the queen in the late 

 summer. The active season of such a nest is 

 shorter than that of Apis or Vespa, the closed 

 time longer. The final activity of the corporate 

 life is the rearing of queens in the later part of 



