86 THE entomologist's record. 



on the contrary, it represents a distinct type round which the indi- 

 viduals tend to group themselves, the intermediate forms between it 

 and the type being less common. I propose to name it ab. ohlita (n. ab.), 

 which may be described as : — 



Ab. ohlita, n. ab. — Alls anticis baud paulo obseurioribus, quasi linearum 

 transversarum colore oblitis. 



As regards intensity of the transverse lines ; in the male they are 

 usually rather faint, especially that portion of the outer line nearest 

 the central spot, and, in some specimens, they are so faint that they 

 can only be traced on the costa, central nervure, and inner margin. 

 In the opposite direction of variation, the transverse lines, though 

 never very dark, are often distinctly traceable through their whole 

 length. In the female, the transverse lines are usually very distinct, 

 and grouped into conspicuous transverse bars. Some prettily marked 

 Enniskillen specimens have the ground colour quite pale and. the bars 

 very dark and distinct. As regards position, the bars tend to 

 approximate to each other. This form of variation is shown in its 

 incipient stage on the nervures near the inner margin, but, occasionally 

 the two bars entirely coalesce and swallow up the pale median area and 

 central spot, producing a form which corresponds with 0. dilutata ab. 

 latifasciata, Prout. I have one male specimen which combines these 

 three tendencies of variation, darkening of the ground colour and 

 approximation and intensification of the transverse bars, the result 

 being a light brown ground colour with darker brown broad median 

 band. Another specimen has a narrow median bar including the 

 central spot, and bounded by a lighter area on each side, as if the 

 encroachment of the light areas had compelled the two bars to retreat 

 towards each other till ultimately they coincided on what ought to be 

 the pale median area. 



Sexual dimorphism, — At Enniskillen, there is a great difference 

 between the sexes, the markings being more conspicuous in the most 

 faintly marked females than in the most distinctly marked males, and 

 much more conspicuous than in the Kannoch females represented in 

 Entom., xxxii., pi. ii. In ab. oblita the male has a decidedly blurred 

 appearance, but, in the female, if the ground colour is dark, the 

 markings are darker, and still distinct. I have, however, one female, 

 a very small captured specimen, which strikingly resembles the male 

 in markings — pale grey, with transverse lines hardly visible except 

 on margins and nervures. In ab. oblita at Epping, to judge from the 

 few specimens I have seen, the female preserves the outlines of the 

 bars distinct in spifce of the darkened ground colour. At Eannoch, 

 the female more nearly resembles the male, the transverse lines being 

 not very dark, and sometimes blurred as in the male. I have also 

 two rather indistinctly marked females from Oban. 



Larva. — I cannot distinguish the larva from that of O. dilutata. 

 There is the green form without dark markings, and the red or purple 

 form with hardly any suggestion of green, and there are all the 

 intermediate forms, and these may all occur in the same brood. I 

 once thought I had discovered that the dark markings in 0. christyi, 

 where they occurred, were always smoky-black and not red. I am 

 now sure that this is not so, for I have had many red-marked 0. 

 christyi larvae, but I still think that the black-marked form is 

 commoner in O. christyi than in 0. dilutata. 



