NEPTICULA POTERII. 249 



dark fuscous. Abdomen and legs grey. Anterior wings pale 

 golden-brown, with a rather broad, straight, pale golden fascia 

 beyond the middle ; apical portion of the wing violet, with violet- 

 grey cilia. Posterior wings pale grey, with pale grey cilia (Stainton, 

 Entomologist'* Annual, 1858, p. 96). 



IMAGO. Head ferruginous. Anterior wings 4 mm. in expanse; 

 pale golden brown in colour ; a rather broad straight pale golden 

 fascia beyond the middle ; apical portion of the wing violet ; cilia 

 violet-grey. Posterior wings and cilia pale grey. 



COMPARISON OF N. POTERII WITH N. MICROTHERIELLA AND N. PLAGI- 

 COLELLA. The species appears to be about intermediate between N. 

 microt/teriella and X. plaijicolclla. It is of about the form and size of 

 the former, thus smaller and with narrower wings than X. playicolella , 

 but the fascia is broader and more shining than in N. niicrotheriella, 

 though less brilliant than in N. playicolella. The fascia in N. poterii 

 is almost further from the base on the costa than on the inner margin ; 

 in the other two species the fascia has a tendency in the other direc- 

 tion (Stainton). From X. betulicola it may be readily distinguished 

 by the position of the fascia, which is placed much nearer the apex in 

 JV. betulicola than in N. poterii. The fascia in N. poterii is inter- 

 mediate in brilliancy between the fascia in N. playicolella and that in 

 N. microt/icriella, being less brilliant than the former, yet not so dull as 

 in the latter. In N. poterii the fascia is almost straight, having, if 

 anything, a tendency to slope towards the base on the inner margin ; 

 in N. plaijicolella and X, microtlieriella the inclination of the fascia is 

 in the converse direction. N. poterii has the anterior wings narrower 

 than X. plai/icolelld, in that respect closely resembling X. microtlieriella. 



EGG-LAYING. The egg is laid on the upperside of a leaflet of 

 Poteriumsanyuisorba, in the example sent us for examination by Fletcher. 

 It is placed at some distance from the margin of the leaf, is very con- 

 spicuous and silvery looking. The young larva, on hatching, at once 

 strikes out for the margin, which it follows. 



MINE. The first part of the mine is exceedingly slender, the excre- 

 ment dense and practically filling it. It Avinds in and out of the 

 serrations of the leaf, and then turns back on its course, passing back 

 parallel' with its first direction, and still leaving a dense blackish 

 frass-line. It then mines towards the centre of the leaf, leaving a 

 wide margin on either side of the frass-track, which is spread very 

 diffusively over the centre of the mine. The small leaf at last is 

 converted almost entirely into a blotch, but the nature and direction 

 of the gallery is readily followed, owing to the regularity of the frass- 

 track, and the remnants of uneaten parenchyma that here and there 

 edge the mine. Stainton writes : " The mine commences as a very 

 slender gallery, passing in and out the serrations of the leaf, and 

 nearly filled with dark grey excrement. After passing nearly round 

 the edge of a leaf, the larva mines towards the centre, eating out the 

 central portion of the leaf, so that the mine then appears almost a 

 blotch." 



LARVA. Length, li lines. Dark amber in colour, with the dorsal 

 vessel brownish. The head brownish-amber, the mouth and sides of 

 the head a little darker (Stainton). 



COCOON. The cocoon is spun on the ground, and is of a brownish- 

 ochreous colour. 



