17S [August, 



NOTES ON THE LIFE-HISTORY OF PHALONIA VECTISANA, 

 Westw., WITH DESCRIPTIONS OF THE LARVA AND PUPA. 



BY EUSTACE E. BANKES, M.A., F.E.S. 



Having failed to find any reliable published information about 

 the life -history of Eupcecilia vectisana, or any descriptions of the 

 larva or pupa, I have drawn up the following notes in the hope that 

 they may be of use. The description of the larva was made on 

 September 16th last from specimens, about full-fed, selected out of a 

 bountiful supply which Mr. W. H. B. IFletcher had very kindly col- 

 lected for me in the saltmarshes at Shoreham, Sussex, on September 



12th. 



LARVA. 



Length, 8"5 mm. Greatest breadth, 16 mm. 



Head polished, brownish-amber, much narrower than the prothoracic segment ; 

 upper mouth-parts dark crimsonish ; ocelli distinct, black, polished. Prothoracic 

 plate polished, pale greenish-amber, inconspicuously divided across the centre by a 

 pale apple-green line. The thoracic and abdominal segments viewed together form 

 a mass which is stout in the middle and tapers somewhat towards the head and 

 gradually towards the anal extremity ; in colour they are pale apple-green, lightly 

 tinged with pink over the dorsal and subdorsal regions ; skin smooth and shining. 

 The pulsating dorsal vessel shows through the skin as a darker dorsal line, and in 

 male larvae the embryo testes show through the back of the fifth abdominal segment 

 as a dark blotch. Warts extremely small and inconspicuous, black, polished. Anal 

 plate polished, pale greenish-amber, with some rather long bristles springing from 

 it. Bristles and hairs pale, but mostly very short and inconspicuous. J'entral 

 surface, and prologs, pale apple-green. Legs polished, very pale amber. 



About a dozen larvae, varying in size, though apparently all in their last skin, 

 were extracted from their burrows, but they did not show any marked differences 

 from one another. I only succeeded in finding one quite small larva : it measured 

 4*5 mm. in length, and had the head and plates decidedly browner than those 

 described above, and the thoracic and abdominal segments were dirty ochreous, 

 instead of apple-green. 



The larva enters one of the shoots of its food-plant, TrigJocMn 

 mnritimiim, either a few inches above, or only just above, the crown of 

 the plant, and works its way downward, eating out the pith of the 

 shoot, and sometimes burrowing into the crown itself. It moves 

 readily from one shoot to another, and its presence may be detected, 

 though not without close scrutiny, by the yellow appearance of the 

 infected shoot, and often by the pale straw-coloured frass, of which 

 some of the fine pellets ax'e generally visible outside the burrow. 

 When full-fed some of the larvae gnawed their way from above into 

 the upper broken ends of the dead flower-stems of their food-plant, 



