58 THE MOTHS OF THE BRITISH ISLES. 



tinged with reddish in some English, and more generally in 

 Irish, specimens. The silvery oblique lines, or bands, vary in 

 width, and sometimes there is a distinct spur from the lower 

 outer edge of the first band. 



The caterpillar is yellowish green, with a rather darker green 

 line along the middle of the back, and a yellow one on each 

 side of it. It feeds on grasses, such as Poa aquatica and P. 

 pratensis^ etc., in July and early August. 



The moth is out in June, and may be found during the day 

 sitting about on the herbage in its marshy haunts, or flying 

 over the vegetation towards the evening. 



The species is exceedingly local in Britain. In ancient times 

 it occurred in Norfolk, but in the present day it seems to be 

 confined to Cambridgeshire, in which county it was first noted 

 rarely in Wicken fen about thirty years ago, but in 1882 it was 

 found plentifully in Chippenham fen, and in that locality (which 

 is a private one) the species still flourishes. In Ireland it is 

 well distributed over co. Kerry, and is especially abundant on 

 the bogs of Killarney. 



The range abroad extends to Amurland, where the brownish 

 form var. amuriila^ Stand., is found. 



The SilYer Hook {Hydrella {Erastrid) unctila). 



The usually olive brown central area of the fore wings is 

 sometimes reddish tinged, and in fresh specimens the whitish 

 front marginal streak is distinctly rosy ; the reniform stigma, 

 which appears to be a spur of the costal streak, is also white 

 or rosy tinged, and sometimes encloses a greyish mark. This 

 stigma is the so-called "hook" to which both the English 

 name and the Latin specific name refer. (Plate 21, Fig. 5.) 



The caterpillar feeds in July and early August on sedges 

 {Carex) and coarse grasses. It is green, with three lines along 

 the back, the central one rather darker green, and the other 



