CIV. PRESIDENT S ADDRESS. 



advantage to the species which practises it, in enlarging its 

 limits and preventing close inter-breeding, which would be 

 detrimental to it. Again, it is a necessary portion of the 

 economy of some species, as in the swarming of the honey- 

 bee. In the great majority of instances, however, we can see 

 no definite advantage, and in the present state of our know- 

 ledge, or, I may rather say, ignorance, of the subject, we can 

 only suggest that it is perhaps a habit transmitted from ancestors 

 to whom it was of some special value, the value having now, in 

 a changed condition of circumstances, ceased to exist, except in 

 a few isolated cases. 



It is in the power of everyone to observe these phenomena, 

 and it is only by the careful observance and record of facts that 

 we shall ever arrive at the true explanation of Insect Migration. 



