154 LEPIDOPTERA. 



slender antennee ; a,ud the fore wings often paler grey or 

 whitish-grey ; abdomen shorter and thicker ; otherwise 

 similar. 



Underside of the fore wings dull pale smoky-grey ; costa 

 and nervures faintly tinted with brown ; discal spot and 

 second line obscurely perceptible. Hind wings greyish- 

 white, dusted closely with purplish-grey; central spot hardly 

 visible. Body pale grey ; legs not tufted, grey-brown. 



Variable only in depth of colour ; casual specimens of both 

 sexes are considerably blackened ; but those obtained in the 

 Hebrides are pale, the females sometimes conspicuously so. 

 A specimen in Dr. Mason's collection is unicolorous shining 

 grey-brown, without markings, but with the nervures faintly 

 darker, fore and hind wings alike. 



On the wing in July and August. 



Larva very stout and stiff, cylindrical in the middle, 

 slightly flattened at the extremities ; the spiracular region 

 forms a puckered ledge ; legs short ; head smaller than the 

 second segment, and tucked in ; general colour, including the 

 head, grey, in some specimens becoming gradually paler 

 behind ; on the front segments a fine double dorsal line 

 encloses a whitish-grey thread, but afterwards this double 

 line appears only as a small elongated spear-head in the 

 middle of each segment; the subdorsal line is a fine waved 

 pale thread, edged with black, and bearing thick dark dashes 

 at the beginning and end of the segments ; the tubercular 

 warts are whitish with dark rings, the dorsal pair on the 

 twelfth segment placed close together, and being more 

 developed than the rest, stand up as obtuse points; the 

 warts, in a row on the thirteenth segment above the anal 

 flap, are very small and black in colour ; the spiracles are 

 pale brown ringed with black, and are placed in a stripe of 

 dark grey, with darker dashes at the folds, and some fine 

 dark streaks, wavy and sloping upwards ; this is followed by 

 a line of whitish-grey which melts into the grey or reddish- 



