SOLITARY AND SOCIAL BEES 



queens are produced. It is not known what exactly deter- 

 mines the date when this shall begin. It is not simply that 

 the vigorous, successful colony shall have passed a certain 

 size, for relatively small colonies may produce one or two 

 queens at about the same date as a larger colony of the same 

 species produces a much bigger number. It may be that there 

 is some change in the queen's rate of egg-laying, so that the 

 number of nurses tends to pile up compared with the number 

 of grubs to be looked after. Among the brood which hitherto 

 has produced nothing but workers a certain number of 

 males appear and a little later queens. After this no more 

 workers are produced. This sequence, in which males 

 tend to precede the queens but partly develop among 

 them, is exactly what is recorded in the common wasp. 

 The young queens work only in colonies in which the 

 workers are for some reason scarce. Normally, they stay in 

 the nest for a time to feed, and then, after pairing, enter 

 winter quarters. , 



At this season of the year, one may notice several bees 

 taking the same course in a garden or wood, though there 

 may be a few minutes between one flier and the next. At 

 intervals, they will fly down and hover for a moment in such 

 places as the hollow at the roots of a tree. These are male 

 humble bees on their characteristic circuit, usually a different 

 one for each species. Humble bees have a strong, often honey- 

 like smell in the male and a less obvious, often rather un- 

 pleasant smell in the queen. It has been suggested that the 

 males emit scent at the stopping places on their circuit and 

 that these are then attractive to. the young queens; the 

 suggestion has, however, not been studied experimentally. 

 But R. A. Cumber found that young queens could be 

 suspended by a piece of cotton in bushes in the circuit, and 

 that males would then soon come and pair with them. In 



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