MALACOSOMA CASTKENSIS. 533 



described as reddish-grey or fawn-colour, with transverse yellow fasciae, 

 replacing the normally dark transverse lines in the male. The hind- 

 wings may have a faint transverse shade, although this is frequently 

 absent. The best marked British female forms are : 



(1) Forewings entirely yellow-ochreous with little trace of paler lines ; hind- 

 wings also yellow-ochreous = ab. taraxacoides, Bell. 



(2) Fore- and hindwings fawn colour, with two distinct transverse yellow 

 fasciae ; forewings with the basal area also yellow, leaving the median band and 

 outer margin of the redder ground colour = ab. virgata, n. ab. 



(3) Fore- and hindwings fawn colour, the forewings with two distinct trans- 

 verse yellow fasciae =? castrensis, Linn. 



(4) Fore- and hindwings unicolorous fawn colour = ab. unicolor, n. ab. 



(5) Forewings red-brown, with markings as in 2 = ab. rufo-virgata, n. ab. 



(6) Forewings red-brown, with markings as in 3 = ab. bifasciata, n. ab. 



(7) Forewings red-brown, with little trace of the yellow transverse fasciae = 

 ab. veneta, Stdfss. 



(8) Fore- and hindwings unicolorous red-brown = ab. hilleri, Stdfss. 



A peculiar modification of 2 often occurs in some $ s, in which the lower 

 part of the median transverse band of the forewings is also suffused 

 with yellow, making it, as it were, nearer to 1 (as a yellow form), although 

 with the hindwings darker as in 2. We observed in Webb's collection, 

 three very remarkable females : (1) An exceedingly deep red-brown, 

 almost like the deepest fox-coloured M. neustria, but with the ordinary 

 pale fasciae. (2) A peculiar example, of a tint between yellow and 

 red-brown, both shades as it were to be seen equally developed ; the 

 fasciae practically obsolete. (3) An example of an unicolorous pale 

 livid buff. Stephens states that scarcely two specimens of this incon- 

 stant species are precisely similar, they vary so greatly. Bacot observes 

 that 77 specimens — 44 females and 33 males — bred from one batch 

 of larvae in 1899, show great variation in size and colour. The colour 

 of the males extends from creamy-yellow to dark amber on the fore- 

 wings — intermediate shades being present ; the hindwings show a less 

 range, but all the pale forms exhibit a tendency to develop remnants 

 of a pale transverse median shade which is entirely absent on those of 

 the dark forms; 15 males may be described as pale, 11 as dark, 

 one is unicolorous ochreous, having almost obsolete markings on the 

 forewings ; the rest are ill-developed or cripples. Of the females, 24 

 have well-marked pale transverse bands across the forewings, in 16 

 these are more or less obsolete ; most of the latter are dark forms, 

 whilst the banded ones show a gradation from dark to a pale ground 

 colour. These obsolete-banded forms rarely have any transverse band 

 across the hindwings, although the well-banded forms generally show 

 traces of this marking. Whittle says that of 70 specimens reared in 

 1890, 59 were males, and 14 females ; of these 52 males were typical, 

 three pale ochreous, with transverse lines only faintly visible, three 

 brownish and one unicolorous deep reddish-brown. Of the females 

 one was ochreous, the rest brownish. In 1897, Whittle bred a pale 

 male with approximating transverse lines, and another male of an 

 uniform red-brown colour, without transverse lines, the larvae of both 

 from Great Wakering marshes. Of the general variation of the species 

 he observes : "I possess specimens of the male which show a range of 

 coloration extending from pale ochreous to deep red-brown ; of these 

 some are well-marked, others bat faintly, whilst yet others are 

 perfectly concolorous (either pale ochreous or deep reddish-brown) 

 without a trace of markings. The wing-space enclosed by the first 



