80 THE ENTOMOLOGIST. 



and the comparative northerly distribution with that of P. csgon. 

 Both occur in southern and middle Scandinavia, but as far as 

 I can gather from the numerous lists and catalogues of Norwegian 

 and Swedish lepidoptera consulted, argus, unlike the argus of 

 middle Europe, is single-brooded as well as legoii. This, of 

 course, is but natural in view of the fact that double-brooded 

 species in the warmer south tend invariably to single broodedness 

 in a more rigorous climate, and often when normally warm 

 summers are abnormally cold. 



JEgon in Britain, in the greater part of France, and I think, 

 in all mountain regions above 3000 ft., has but one emergence. 

 I have taken examples of a second emergence in August on 

 the sunburnt lavender-haunted hills of Lozere. In the lower 

 Pyrenees (following Rondou) there is but one ; even apparently 

 in the warm valley of Le Vernet, which enjoys a Mediterranean 

 climate. In the Basses-Alpes, on the contrary, there appears 

 to be a partial second brood, while in the valley of the Saone 

 as far north as Macon there are clearly two {fide E. Andre, 

 ' Lipids, de Saone-et-Loire ') as the butterfly is recorded at 

 Macon from May to September. And though in Brittany 

 M. Oberthiir has observed but one, Guenee (' Lepids. Eure-et- 

 Loir ') records an August emergence in his department. In 

 the lower regions of Switzerland, e.g. the neighbourhood of 

 Geneva, a second emergence takes place from the first week 

 of July to the first week of September.* 



Pending further accurate information, I am inclined to place 

 the Loire valley in western Europe as the extreme northern limit 

 of the second emergence of (cgon,. as with many other lepidoptera 

 of this habit ; and probably lat. 47° N. may be taken as a more 

 or less likely geonomic of the second brood west of the Urals, with 

 the vertical exceptions to which I have alluded. t 



The case of argus (almost invariably cited as argijrogiiomon 

 by recent authors) is quite otherwise. A second emergence 

 occurs in Brittany, but the species appears to be wanting 

 altogether in the north-eastern departments west of the Seine 

 and north of PJieims (Marne), as, I think, the several notices 

 collated in my MS. catalogue are extremely doubtful, and 

 require modern confirmation. In North Germany one emer- 

 gence only is recorded in Schwerin and Pomerania, in July and 

 August, and at Bremen (Piiibl, ' Pal. Gross-Schmetterlinge,' 

 band i, 233, 752). In Denmark Klocker's record (' Sommerfugle,' 

 i, p. 86, 1908) rather suggests a double brood — " Larva, May- 

 July; imago, June-x\ugust " — but he may only indicate a some- 



* ' Catalogue des Lepids. des Environs de Geneve.' Geneva, 1910. 



i There is a strange error of transcription on p. 163, vol. iii ' British Butter- 

 flies.' Tutt is quoting a passage from Eiihl's description of a 9 arcjus. We read : 

 " Taken at Amboise, at an elevation of 6000 ft." Riihl records Lelievre's capture 

 of the gynandromorph in question. " At an elevation of 600O ft.," begins a new 

 sentence, and refers to the vertical distribution of the species as a wliole ! 



