156 PIERIS EAPI. 



PlEEIS NAPI. 



Plate II, fig. 4. 

 (See Mr. Buckler's brief notice at p. 20.) 



I saw a few butterflies on the wing in May and 

 June of this year, but could not capture a female ; in 

 the beginning of August I was in a locality where the 

 second flight was out in numbers, and on the 10th I 

 captured two females, which on the 12th began to lay, 

 and in a short time deposited a large number of eggs. 

 The larvae were hatched in six days' time, on the 18th ; 

 in four days passed their first moult, August 22nd ; four 

 days afterwards came the second moult, August 26th ; 

 and in three days more the third moult, August 29th ; 

 and in four days more the last moult, September 2nd. 

 The first pupa was developed September 8th, and the 

 last September 14th; none of them have so far dis- 

 closed the imago, and no doubt are lying over for the 

 first flight in next year. Mr. C. Gr. Barrett kindly 

 sent me some eggs from Belfast August 25th, and the 

 larvae appeared next day. I saw the butterfly on the 

 wing up to September 9th. 



1 have never seen the larva at large, but I fed those 

 I have reared this season on horse-radish, which they 

 seemed to like very well, eating the leaves and the 

 stout leafstalks voraciously. Mr. W. H. B. Fletcher 

 tells me he has found it on Nasturtium officinale, and 

 abundantly on a small cress growing in ditches in the 

 New Forest, which he took to be Barbarea vulgaris ; 

 Mr. W. H. Harwood believes he has found it on Calrile 

 maritima. 



The egg is laid singly, on end, and is flask-shaped, 

 being 1J mm. in height, nearly \ mm. wide, and about 

 -g- mm. across the top, with (generally) fourteen longi- 

 tudinal ribs not meeting very neatly, and with regular 

 delicate transverse reticulation ; colour at first pale 

 green, afterwards becoming more pale and silvery; 

 thus, although much like the egg of rajpce, it is longer, 



