138 OARADRININA [metachrostis 



1. Median band suffused with fuscous . 3. algae. 



,, ,, not fuscous . . .2. 



2. First line reaching dorsum . . 1. perla. 



,, ,, not reaching dorsum . . 2. muralis. 



1. M. perla, F. 22-27 mm. Forewings ochreous-whitish ; 

 costa marked with blackish ; lines black, subbasal preceded by 

 a greyish spot, second subdentate, subterminal forming dots ; 

 spots grey, sometimes bluish -tinged, orbicular and claviform 

 confluent to form an 8-shaped spot, reniform similar, smaller, 

 whitish - edged ; a greyish praesubterminal costal spot; a ter- 

 minal row of white dots, surrounded by greyish suffusion. 

 Hindwings grey-whitish ; discal spot and two suffused posterior 

 lines dark grey. 



Britain to Caledonian Canal, Ireland, common ; C. and SW. 

 Europe ; 7, 8. Larva light bluish-grey ; a broad irregular 

 orange or ochreous-yellovv dorsal stripe, usually enclosing an 

 interrupted dark grey dorsal line ; lateral and spiracular lines 

 sometimes whitish ; spots black ; head black : on lichens on 

 walls; 10-5. 



2. M. muralis, Forst. {glandifera, Hb. ; par, Hb. ; impar, 

 Warren) 25-29 mm. Forewings whitish-greenish ; costa marked 

 with black ; lines black, subbasal preceded by a grey-greenish 

 suffusion dorsally prolonged, first connected with subbasal near 

 dorsum and not reaching dorsum, second and subterminal fol- 

 lowed by grey -greenish shades; spots grey -greenish, outlined 

 with black, orbicular and claviform confluent into a transverse 

 blotch. Hindwings light fuscous ; discal spot and two suffused 

 posterior lines darker. 



England to Caernarvon and Norfolk, W. and S. Ireland, 

 local ; C. and S. Europe, Asia Minor ; 7, 8. Larva bluish-grey ; 

 dorsal line white, irregular, sometimes interrupted ; subspiracu- 

 lar pale or yellowish ; spots white ; head and plate of 2 black : 

 on lichens on walls ; 10-5. 



3. M. algae, F. 22-25 mm. Forewings grey-greenish, median 

 band suffused with fuscous ; subbasal line black ; first and 

 second indicated by some whitieh scales, edged internally with 

 blackish ; a semicircular dorsal spot outlined with blackish 

 beyond subbasal line ; spots hardly darker, orbicular and 

 claviform confluent into a transverse blotch ; subterminal line 

 obscurely whitish. Hindwings fuscous, darker terminally. 



Cheshire, Lancashire, very scarce ; C. and S. Eiirope, Asia 

 Minor; 7. Larva greenish-grey, whitish - mixed ; doi'sal line 

 and lateral spots white ; dorsal series of black horseshoe- 



