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JOURNAL OF VARIATION. 



No. 8. Vol. VI. May 1st, 1895. 



/IboYe La^e Boupget. 



By J. W. TUTT, F.E.S. 

 The heat, of the late August sun is tempered in the early morninc»-, 

 although it shines brightly in a cloudless sky of deepest azure. Our 

 nets are put into order as soon as we step from the train at the little 

 wayside station of Grdsy-sur-Aix. Gresy is five or six miles to the 

 north of Aix-les-Bains, and the delightful-looking country has tem^jted 

 us to explore its mysteries during the few hours that we have at our 

 disposal. 



When the train has steamed out of the station, we leave the little 

 lane into which we first entered and, l)y a level crossing, pass over the 

 rails, and make for some low hills that lie a little to the west of the 

 railway. The mowers' scythes ring out blithely in the morning air, 

 as we walk by the side of the clover fields where they are at work ; a 

 few fragile-looking white butterflies show us that Lemophasia sinapis is 

 taking its morning flight. Have you ever held a specimen of the Wood 

 White butterfly against the light and traced the nervures of its fore- 

 wings ? The discoidal cell at the base is restricted to an extent that is 

 never seen in other British butterflies, whilst the nervure which runs 

 from it to the apex of the wing is a most complex structure, for all the 

 branches which are usually given off from the top of the discoidal cell 

 itself, when it is of normal size, are here given off from the nervure 

 which represents the extension of the upper boundary of the discoidal 

 cell, and not from the cell itself. Compare, too, the sim})le structure 

 of this same nervure in Aporia and Pieris, with the more complex one 

 in Enchloi', and then with the still more com})lex one of Leucophasia. 

 Dr. Chapman has formulated a theory that those l)utterflies whose pupje 

 have tbe greater number of movable abdominal segments are lower in 

 the scale of develojnnent in their own particular group, than those 

 whose pupfe have them fixed, and he traces up the Pieridae on these 

 lines in the following ascending sequence : — Aporia, with three movable 

 incisions (two free segments) ; Pieris, with two movable incisions (one 

 free segment) ; Emhlo'-i and Leiicophafiia, with no movable incisions, 

 the pupa being solid. The complexity of the nervure forming the 

 upper part of the discoidal cell and running towards the apex of the wing, 

 increases as we ascend through the same genera, so that one cannot help 

 considering the two sets of facts as pointing to the same conclusion. 

 Colias hyale, too, is on the wing, and in a rather narrow lane we meet 



