CATKIN TIME 59 



one small reddish ' o ' like a fungus-mark on the 

 leaf-shaped wing, the spirit of spring is off again. 

 It is making a search, which would puzzle most 

 botanists hereabouts, for a bush that, when it comes 

 into leaf, will declare itself to be buckthorn, for it 

 is on that plant that brimstones' eggs must be 

 laid if the caterpillars are to live. I may confess 

 that I have never seen the buckthorn here ; yet 

 that it is to be found the punctual appearance of 

 fresh-and-fresh brimstones in July seems to testify. 

 I cannot say that the butterfly succeeds in 

 identifying the plant before it is in leaf, for I do 

 not know that the eggs have been found before 

 May, and then they are fixed on the leaves them- 

 selves. But what wonderful instinct is this that 

 enables a honey-living creature to select from all 

 the leaves of the forest that one which its larvae 

 must eat if they are to grow up into butterflies 

 themselves ? 



