HYDRIOMENA] HYDRIOMEN1DAE 213 



suffused with green-whitish ; a dark fuscous apical dash : some- 

 times whole wing suffused with rather dark fuscous ; a form 

 occurs with ground-colour ferruginous -ochreous, markings 

 blackish. Hindwings fuscous ; a darker discal dot. 



Britain to the Orkneys, Ireland, very common ; N. and C. 

 Europe, N. Asia, Japan, N. America ; 7, 8. Larva brown or 

 blackish ; dorsal line double, white ; subdorsal and lateral white ; 

 spiracular area pale red-brown : on Salix, hawthorn, etc. ; 4-6. 



12. H. trifasciata, Bkh. (impluviata, Hb. ; liter -ata, Don.; 

 ruberata, Frr.) 28-32 mm. Forewings dull olive-green, mixed 

 or strigulated with dark fuscous, sometimes wholly fuscous ; 

 edge of basal patch indicated by a blackish oblique line ; second 

 and fifth fasciae fuscous, irregular; median band pale, edges 

 dark fuscous, waved, posterior with double rounded median 

 projection ; a small dark fuscous discal mark ; an oblique sub- 

 apical series of three or four blackish marks. Hindwings 

 fuscous ; a darker discal dot and two postmedian striae. 



Britain to the Orkneys, N. Ireland, common ; N. and C. 

 Europe, N. Asia, N. America; 5, 6. Larva pinkish-green or 

 pinkish-grey, marked with ochreous or dark brown ; dorsal line 

 darker ; subdorsal pale, darker -edged ; spiracular pale or 

 whitish : on alder, Salix, and poplar ; 7-9. 



13. H. truncata, Hufn. (russata, Bkh.; immanata, Hw.) 

 26-33 mm. Forewings ochreous -brown, marked on veins or 

 wholly suffused with dark fuscous ; basal patch dark fuscous, 

 edge angulated above middle, sometimes white -margined ; 

 median band dark fuscous, sometimes white -edged, central 

 space often suffused with white, sometimes with yellow- 

 ochreous, posterior edge with double median projection, 

 upper lobe larger, slightly bifid ; an oblique black discal 

 mark ; subterminal line whitish ; sixth fascia mixed with dark 

 fuscous and whitish. Hindwings grey, sometimes ochreous- 

 tinged ; a darker discal dot and postmedian angulated stria. 



Britain to the Shetlands, Ireland, common; N. and C. 

 Europe, N. and C. Asia, N. America; 5-9. Larva slender, 

 green, with yellow -whitish tubercles; dorsal line dark green; 

 subdorsal pale ; sometimes a lateral purple-rosy stripe ; 13 with 

 two rosy points : on Fragaria, Polygonum, sallow, etc. ; 4-8. Two 

 forms of this species (often regarded as specifically distinct) are 

 generally but not always distinguishable in Britain, viz. trun- 

 cata, in which the angle of the postmedian stria of the hind- 

 wings is obtuse, and immanata, in which it is acute ; but the 

 species is even more variable in the Asiatic and American 



