THE MIGRATION OF BUTTERFLIES. 



345 



(2) The sexes do not migrate separately as is the case with 

 certain birds. 



(3) Butterflies do not invariably fly with or before the wind. 

 They have been observed passing from S.S.E. to N.N.W., with 

 the wind at S.S.W., and even going due W. with the wind 

 blowing from that quarter. This negatives the suggestion that 

 they are irresistibly carried away by a current of air. 



Weitswetl 



Wurt&mbxirg. 



£i8cheuri\ 



Wurtemburg. 



Diagram to show prevailing direction of Migration of 

 Vanessa cardui, 



(4) The general direction of the spring migration (at least 

 in the case of V. cardui) is northerly ; that is to say, not due 

 north, but some points E. or W. of N., as shown in the accom- 

 panying diagram. In no instance, so far as the records show, 

 have any flocks been observed at that season of the year going 

 south, or in any southerly direction. 



(5) There is no return journey in autumn in a direction 

 opposite to that taken in spring. 



There are other points upon which no certain information is 

 at present available. For example, we have yet to learn whether 

 butterflies have a sense of direction — as is probable, not merely 

 from what has been above stated, but from their going towards 

 particular flowers, and making choice of particular food-plants 

 upon which to deposit their eggs — or whether in the course of 



