The Influence of External Conditions 25 



whose growth occurs in late autumn (with lower temperature 

 and decreasing vegetation) and is completed in the autumn so 

 that they winter as pupae, are generally smaller in the first gen- 

 eration and larger in the second or summer generation: for 

 the caterpillars of the latter are bom in summer and have plenty 

 to eat. Conversely, species which winter over as small cater- 

 pillars and develop further during the favorable conditions of 

 spring produce larger butterflies in the first than in the second 



LITERATURE. CHAPTER H 



Bachmzitzw. p. Ueber die Temperatur der Insecten nach Beobachnm- 



gen in Bulgarien. Zeit. f. wissen. Zool. LX\X 1899. 

 Der kritische Punkt der Insecten und das Entstehen von Schmetter- 



Ung^-aberration. HI. Zeit. f. Entomol. V. 1900. 

 Experimentelle entomologische Srudien. i. Band. Temperaturver- 



haltnisse bei Inseaen. Leipzig. 1901. 

 Kalometrische Messungen an Schmenerling^puppen. Zeit f. wissen. 



Zool. LXXI. 1902. 

 Batesox. W. On Variation in the Colour of Cocoons of Eriogaster 



Trans. EntomoL Soc. Ivondon. 1892. 

 On Variation in the Colour of Cocoons, Pupae, and Lanae; Further 



Exp>eriments. Ibid. 1892. 

 BstrcKE. E. Ueber den Farbenwechsel der Chamaeleonen. Sitz. Kais. 



-Vkad. Wiss. Wien. math.-natuiw. CI. VII. 1S51. 

 Untersuchimgen ueber den Farbenwechsel des Afrikanischen Chama- 



leons. Denkschr. Kais. Akad. Wiss. Wien. math.-naturw. CI. I\'. 



1852. 

 C.\XLTOX. F. C. The Colour Changes in the Skin of the so-called Florida 



Chameleon. .Anolis Carolinensis Cuv. Proc. of the Amer. Acad, of 



Arts and Sci. XXXIX. 1903. 

 Chlodkovsky. X. Sur quelques Variations Artificielles du Papillon de 



rOrtie (Vanessa urticaet. Ann. Soc. Entomol. de France. LXX. 



1901. 

 DiXEY, F. A. On the Phylogenetic Significance of the Wing marking in 



certain Genera of the Xymphalidae. Trans. Entomol. Soc. Lon- 

 don. 1S91. 

 Mr. Merrineld's Experiments in Temperature -Variation as Bearing 



on the Theory of Heredity. Trans. Entomol. Soc. London. 1S94. 

 DoRTMEiSTER. G. Ueber die Einwirkung verschiedener wahrend der Ent- 



wickelungsperiode angewandter Warmegrade auf die Farbung und 



Zeichnung der Schmenerlinge. Min. d. naturw. Ver Steiermark. 



n. 1864: 

 Ueber den Einfluss der temperatur bei der Erzeugung von Schmener- 

 linge varietaten. Ibid. 1879. 

 Edwards^ W. H. An Abstraa of Weismann's paper on "The Season 



Dimorphism" of butterflies, to which is appended a statement of 



