44: VARIETIES OF NOOTUJfi 



Gregsori writes: "I have several of this form (ollvacca) ; one, given 

 to ine by Mr. Allis, is of the darkest green I have seen, the body 

 being dark brown, and one, obtained near Lees, near Oldhani, is dark 

 brownish-olive, with the markings very light. The latter is a most 

 striking instance of change of colour " (' Entomologist,' vol. iv., p. 54). 



ft. var. mffasa, Robson. This form has the fore wings of a cold 

 dark-grey in both sexes, and has been described by Mr. Robson, who 

 writes : " In the Cleveland district of Yorkshire, the type form of 

 P. chi is very common and may be taken in any number at rest on 

 the stone walls that form boundaries on the moors. In West York- 

 shire, another form occurs, distinct enough to have a varietal name. 

 Instead of the pure white of the type, it has the ground colour much 

 suffused with grey. It is scarcely so dark as captured olivacca, and 

 is entirely without the greenish hue of that variety. Stt/'tisa would 

 be an appropriate name for it. I know little of the species from other 

 places. The few Scotch specimens I have seen, all have the pure 

 white ground of the type " (' Entomologist's Record ? &c., vol. ii., p. 84). 

 Mr. Robson also writes : " Mr. L. S. Brady of Sunderland has sent 

 for my examination a specimen of Folia chi, the larva of which he 

 obtained, along with those of several species of Tceniocampa, 'by beating 

 in 1883, at Arthog, in North Wales. The moth did not emerge in 

 August or September, as usual, but came out in the spring of 1889 with 

 the specimens of Twniocampa. The specimen sent me is of a darker grey 

 variety, which, I believe, has no varietal name yet, but which I have 

 always known as the Yorkshire form " (' Young Naturalist,' vol. xi., 

 p. 234). I have always known this variety as the Bradford form, 

 due, I suppose, to the Yorkshire collectors in that neighbourhood 

 having been the first to notice it. There is, of course, a tendency for 

 the ground colour of typical females to be darker than the typical 

 males, but in var. sujf'usa, the ground colour of the males also under- 

 goes a darkening process. 



y. var. nigrescent! , mihi. At the meeting of the Ent. Soc. of 

 London, on February 10th, 18 ( J2, Mr. Porritt exhibited almost nielanic 

 specimens of Polta chi of which he writes : " The melanic specimens 

 of P. chi which I exhibited at the meeting of the Entom. Soc. of 

 London on the 10th inst., differ from the ordinary type in having the 

 usual pale markings replaced by slaty-red colour in the fore wings of 

 the males, and by dark olive- lead colour in the females. The hind 

 wings are paler in the male, but as dark or even darker than the 

 forewings in the female " (in litt.). This form was first noticed by 

 Mr. Porritt who wrote : " An almost melanic form of P. chi in both 

 sexes has been captured here (Huddersfield) both this and last season " 

 (' Entom. Record ' &c., vol. iii., p. 7), although there is a reference to 

 black forms having occurred in the Leeds district by Mr. Mansbridge 

 in the ' Entom. Record ' &c., vol. ii., p. 200. 



Folia, Tr.. xanthomista, Hb. 



A local form of this variable species is found in the Isle of Man 

 and Cornwall. There appears to be a very great range of variation 

 in this species on the Continent, and a tendency to develop local races 

 through the action of " natural selection " in different localites is ob- 

 served. In certain parts of Switzerland, var. nivcsccns only occurs, in 





