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THE ENTOMOLOGIST. 



different, the conditions for the development of direct seasonal 

 dimorphism are not given, as is also the case with V. urticce. 



Merrifield also has recently made experiments with Pararge 

 egeria, and I should very much like to be able to compare his 

 results with my own. Apparently they contradict one another, 

 in so far as my German brood of egeria were not altered by 

 32° C, while his pupae, under the same treatment, produced 

 butterflies with smaller and less sharply defined bright spots, 

 and also with a considerably lighter ground colour. 



With all respect for the great accuracy with which Merrifield 

 obviously works and observes, I might yet suspect that the 

 differences, which he here observes, are not far-reaching ones, 

 but small individual variations, which are not connected with 

 the increased temperature. I myself at first thought I saw 

 constant differences between those specimens which were forced 

 in the incubator and those developed at a room temperature, but, 

 after a careful comparison of all my specimens, I saw my mis- 

 take. It would also contradict what we should expect, if our 

 egeria had smaller spots from heat, as vieione has them larger. 

 For the rest, it is interesting to be able to confirm my earlier 

 conjecture, that meione is the primary and egeria the secondary 

 form, in the markings of the butterfly itself. P. meione has, 

 indeed, more numerous and larger spots ; thus, for example, 

 there are five on the costa, while often only two are distinct in 

 egeria. But two or three of the others may be generally recog- 

 nised in egeria as faint indications of bright places, in the 

 dark ground colour : "obsolete" (verloschene) spots, as the good 

 and descriptive expression of the lepidopterists has it, which 

 may be taken literally in this case, as these traces can only be 

 explained as vestiges of the spots of the parent form. 



Adaptive seasonal dimorphism.— 1 recently cited, by way of 

 conjecture, the North American butterfly, Lyccena pseiidargiolus, 

 as an example of such among larvce, when I was relying on the 

 very detailed statements of W. H. Edwards He found differently 

 coloured larvae in the summer and autumn broods of this butter- 

 fly. Now the earlier larva is white, and, as Edwards expressly 

 says, well adapted to the white flower- buds of its food-plant, 

 Cimicifuga racemosa ; but the autumn brood is yellowish green 

 or olive- green, and lives on a plant with yellow flowers, which 

 blooms much later — Actinomeris squarrosa ; so it is a question 

 of assuming this latter colouring also to be protective, and of 

 regarding the whole as a case in which the two broods have 

 adapted their colouring to their different food-plants. American 

 entomologists must prove whether this is actually the case. If 

 it is so, then it would be a typical instance of adaptive seasonal 

 dimorphism, inasmuch as the protective significance of both 

 forms is without question. With the tropical butterflies having 

 double seasonal forms, above referred to, it would also certainly 



