PTEEINjE. 165 



Western Himalayas. There it flew very strongly and fast, now under the Horse- 

 Chestnut trees, now in the sunlight over the rocky bed of the stream. I caught one 

 or two in June, resting or fluttering over the margins of the stream " (MS. Notes, 

 1864). " There seems to be two forms of Sanaca, one dark, answering to your 

 description, from Masuri, the other almost v/hite, from Kunawur" (id. Epist. Nov. 

 13th, 1869). In a subsequent letter, to the late Mr. W. S. Atkinson, dated 

 Nov. 18th, 1874', Col. Lang writes: "Sanaca is an early summer insect, and T 

 think local. At my house in Masuri, in May, 1868, I could always see half a dozen 

 in the air, al^vays at a great height, looking like Swifts or Swallows, until your eye 

 was focused and recognized their size and distance ; rarely coming within reach of 

 the longest net, and never setthng unless on tree-tops. This species varies in deptli 

 and breadth of black markings, and, like all the Thi/cas, it is scented like Jargonelle 

 pears." Mr. L. de Niceville (Trans. But. Soc. Lend. 1889, p. 343) says " through 

 the kindness of Mr. P. W. Mackinnon T have received fourteen males and five 

 females of D.Jlavalha and Sanaca from Masuri, and have also before me six males 

 of these two species, also from Masuri, and five males and one iem?i[e flwvalha (which 

 constitute the type specimens of that species) from Kunawur, contained in Col. 

 Lang's Collection, captured by himself many years ago. As regards these latter 

 specimens, Col. Lang in discriminating them and Major Marshall in describing them 

 as distinct species, were quite justified, though both the Masuri and Kunawur 

 groups of specimens are very variable in the amount of black markings they exhibit, 

 on both surfaces, there is no connecting link between them. Mj^ fresh specimens 

 from Masuri supply this link. When arranged in a graduated series from the 

 lightest marked specimen to the darkest, at no point can you draw the line dividing 

 them into two species. Mr. Mackinnon writes me : ' I am sure the dark and light 

 coloured ones belong to the same species, as I got dozens of all shades in one place, 

 and in one forenoon. They were all chasing each other, at times six or seven 

 together. Mine were all caught in open places in forests of Mouroo Oak (Qtiercns 

 dilatata) at Nag Tiba, near Masuri, 5,000 feet altitude, in the latter half of May and 

 beginning. of June, and at Tehri Gurhwal, near Masuri, 8,500 feet, in June. I have 

 seen them often in Masuri, but captured them very seldom.' 1 should remark of 

 the female from Masuri that none of them are as light coloured as the palest male 

 flavala ; in fact, they vary too, but not so much as the male, the lightest specimens 

 e(\}x?A. fiavaJba, the darkest equal Sanaca.'' We possess specimens of both sexes of 

 Sanaca from Masuri, taken by the late Capt. T. Hutton. A female from Masuri 

 is in the British Museum Collection, and a male of the pale form [flavalba) in the 

 Hewitson Cabinet. 



Of our illustrations on Plate 528, figs. 1, la, b, are from the Masuri males, and 

 Ic, d, e, from W. Himalayan females. 



