IN THE BRITISH ISLANDS. 143 



grey (with a greenish tinge) ; short black lines from the base run down 

 the median and basal nervures, whilst a black line, starting from the 

 anal angle, runs parallel to and at a little distance from the hind 

 margin " (' Sammlung Europ. Schmet,' fig. 424). The modified form, 

 with the same ground colour, in which only the transverse median 

 shade is present but not developed into banded form, is called firma 

 by Hiibner. Guenee writes : " One would get a very erroneous idea 

 of this species, a near neighbour to instabilis, if judged by Hiibner's 

 figure. It differs from instabilis by always being slightly smaller ; the 

 superior wings more pointed at the apex ; the subterminal line less 

 broken at the costa, and sometimes quite complete, always continuous, 

 almost straight, shaded throughout its length, without darker wedge- 

 shaped spots ; by the median space being narrower at the bottom and 

 always darker ; by the inferior wings being less powdered and rarely 

 marked with a lunule above. It forms, otherwise, two well-marked 

 races, which, if the description of the larva, given by Treitschke, is 

 exact, might be well separated into two species. That of Hiibner, 

 which inhabits Austria, and which must be considered as the type, 

 has the wings of a clear bluish-grey, with all the markings hepatic- 

 brown, and the extremity of the fringes tinted with the same 

 coloration. It varies little." " Firma, Hb., which I have often 

 considered a variety of instabilis, belongs here. It represents the 

 ordinary form even better than the original figure. However, neither 

 is very exact." Concerning our British specimens, Guenee further 

 writes : " Those from England are of a more ochreous-grey, with the 

 markings smoky-brown, the stigmata more distinct and more clearly 

 surrounded with yellow ; the subterminal line broader, more ochreous, 

 a little more broken at the summit. It appears to be as variable as 

 instabilis, especially in colour. I have a specimen in which the smoky 

 colour has suffused all the wing with the exception of the subterminal 

 line, as in the variety fuscata of instabilis " (' Noctuelles,' vol. v., pp 

 352-353). 



The following is a table of our best known varieties : 



1. Glossy slaty-grey (almost purplish), with a median transverse line 



= var. firma, Hb. 



la. Glossy slaty-grey, with broad central band = opima, Hb. 

 2. Greyish-white, with central shade quite or almost obsolete = 



var. grisea. 

 2a. Greyish- white, with central shade developed into a band = var. 



virgata-grisea. 



3. Greyish-brown, almost unicolorous = var. intermedia. 

 4. Dark-brown, stigmata and subterminal line paler = var. brunnea. 

 4 a . Dark-brown, unicolorous = var. unicolor. 



a. v&r.firma, Hb. This is really a very slight modification of the type, 

 the anterior wings having the same glossy purplish shade, but a little 

 darker in the general ground colour, and the central band of the type 

 becomes reduced to a single dark central shade running between the 

 stigmata. Hiibner's figure may be described as : " Anterior wings 

 dark slaty-grey with the stigmata outlined in bluish-grey ; a dark 

 transverse median shade commences on the costa, passes between the 

 stigmata, and ends on the inner margin ; the subterminal line is 

 blackish outlined with ochreous. Hind wings dark-grey with paler 

 base, lunule very distinct " (' Sanimlung europ. Schmet.,' fig. 676). 



