VARIATION AND ABERRATION IN BUTTERFI-IES. 103 



First in 1864, Georg Dorfmeister published, in the * Mittheil. d. 

 Natiirwiss. Vereins fiir Steiermark,' a memoir "On the Influence 

 of varying Degrees of Temperature, apphed during the Period of 

 Development, on the Colouring and Marking of Butterflies." 

 This was followed, in 1880, by a,nother memoir of Dorfmeister, 

 " On the Influence of Temperature on the production of Varia- 

 tion in Butterflies" (Graz, 1880). 



The best treatise on the subject has been published by 

 Weismann, viz., ' Ueber den Saison-Dimorphismus der Scbmet- 

 terlinge'* (Leipzig, 1875). 



Amongst additional literature on the same question may 

 here be mentioned : — W. H. Edwards, " An Abstract of Dr. Aug. 

 Weismann' s Paper on Seasonal Dimorphism of Butterflies, to 

 which is appended a Statement of some Experiments made upon 

 Papilio ajax" ('Canadian Entomologist,' 1875, No. 7, pp. 228 — 

 240). G. Stange, "Experiments with a lowered Temperature on 

 Aqrotis 'pronuha, L., and Cidaria tristata, L." (Stettin. Entom. 

 Zeit. 1886, p. 279). C. Ed. Venus, in 'Iris' (Dresden, 1888, 

 pp. 209, 210). {V. urticcevfSiS exposed to intense sunlight in the 

 larval and pupal condition.) 



All the above-mentioned treatises deal with the modifications 

 produced by the action of certain degrees of temperature, applied 

 daring the pupal stage, on the aspect of the resulting imngo, in 

 the light of the species by itself — considered, that is, as a 

 separate entity — without reference to its affinities with otber 

 species; and, indeed, the greater number of species hitherto 

 subjected to these experiments have not been forms calculated 

 to open up a further vista of phylogeny. 



We will, however, let the present experiments, with their 

 results, speak for themselves. They were conducted in the 

 following manner : — 



(1) Those pupse only were used whose larvae had fed up at 

 the normal temperature of a room from the middle of May to the 

 middle of August. 



(2) The pupfe were taken for experiment as soon as they 

 appeared perfectly formed and hardened ; when they had lost, 

 that is, the peculiar greasy gloss of most species in a perfectly 

 fresh condition.! 



(3) Most use was made of such species as live in societies, 

 and can therefore be obtained in large broods. In this manner 

 large groups of individuals derived from the same parents, and 

 so bringing to the experiment approximately the same family 

 characteristics, were employed almost throughout. 



(4) One portion of each brood was put into a refrigerator, the 

 temperature of which varied between 5° and 8° C. (41°— 47° F.). 



* Translated and edited in English by Professor Meldola. 

 f Quite fresh pupae are not suited for experiments that involve a lowered 

 temperature. 



