253 



THE BRITISH NATURALIST. 



[December 



ends on the inner margin, the area just beyond this mucli paler ; 

 there is another black linear costal mark towards the tip, two dots at the 

 end of the fissure, and a dark shade in the centre of t]ie wing, running 

 longitudinally from the base, and ending at the junction of the two 

 lunular marks before mentioned. The hind wings are divided into 

 three plumules, dark greyish brown in colour. Stainton's diagnosis 

 is: — "ii"' I" I'". F.-w. whitish-grey, sometimes with a brownish 

 tinge ; a dark blotch posteriorly edged with whitish before the fissure, 

 and dark blotch on the costa beyond it ; the middle pair of tibiae much 

 thickened at the end and in the middle " (" Manual,'" H., p. 443). 



Imago — The type is thus described by Treitschke : — Alucita, 

 alis anticis albido testaceis, atomis striisque longitudmalibus fuscis 

 lunula apicis dilutiore, fimloriis fusco alboque variegatis " (" Die 

 Schmet."' etc., IX., p. 245). A figure of all the different stages and 

 food-plant is given in the May (1882) number of the " Entomologist." 

 The following is Dale's description of similadactyla which has been 

 mistaken for another species " Cinereous ochre or grey, base of 

 head and collar dark-brown, superior wings partially dotted with 

 black, deeply cleft at the apex and falcate ; the costa and inferior 

 margin a little darker, terminating suddenly and forming at the cleft 

 an oblique and darker line partially edged with white, cilia fuscous, 

 inferior wings, tnlobed but simple ; legs white, anterior tibise, with 

 the inside and apex fuscous, intermediate with a buncli of fuscous 

 scales at the middle, and another at the apex, the posierior fuscous 

 outside ; the tips of the joints of the tarsi fuscous. It resembles in 

 size and appearance the J megadactyla, of Hiibner ; but the falcated 

 apex to the lower lobe of tlie superior wings, will at once distinguish 

 it, and the legs are spotted and very similar to those of 

 P. trigonodactylus, Haw ; but it does not belong to the same section. 

 Taken by Mr. G. W. Chant, in the Isle of Wight." (" Magazine Nat. 

 Hist.," Vol. VII., p. 263). There could be no better description of 

 lithodadyla than this, and whatever the similidactyla, Dale, that Dr. 

 Staudinger sells can be, I cannot imagine. 



Variation — There is a very considerable amount of variation m 

 the ground colour and dark markings m this species. On the sand- 

 hills at Deal, the specimens are very pale, and have a slightly 

 ochreous tinge, with the markings frequently almost obsolete,' vvhilst 

 in the marshes they are generally very dark and well marked. In 

 Chattenden, I find dark specimens, with a somewhat purplish tinge, 

 generally well marked but frequently unicoiorous. The variation in 

 this species is well worthy of attention. 



Pupa — Mr. South describes the pupa as follows : Upper part 

 hairy like the larva, colour whitish, much streaked with dark olive- 



