108 THE DISTRIBUTION, RARITY 



in the flight of an insect directly. The late Mr. 

 F. Smith, in his day our leading authority, 

 the Rev. F. D. Morice, than whom no one 

 has probably worked ;the neighbourhood more 

 thoroughly, Mr. T. R. Billups, Mr. E. B. 

 Nevinson, and the late Mr. A. Beaumont, have 

 all been over the ground again and again, and 

 yet only these two Dufoureas I and these taken 

 four miles apart. Here again is a problem which 

 is very perplexing ! What part in nature does 

 this little rarity play ? No doubt like every- 

 thing else it has its duties, and its corner to 

 fill, but beyond that one can suggest nothing. 



Other bees are often exceedingly abundant 

 in one season and very rare the next, or they 

 will entirely desert a locality where they have 

 been abundant, and move somewhere else the 

 occasional scarceness is due probably to continued 

 wet weather, which often appears to kill the 

 larvae. Cold winters seem to have no injurious 

 effect, although at one time they were thought 

 to determine the scarcity or otherwise of the bees 

 of the following summer. It has, I think, been 

 clearly shown that larvae can stand almost any 

 amount of cold, although they succumb to 



