The l7iflMe7ice of External Conditions 17 



The effect of heat on Vanessa atalanta is shown in Fig. 7. 

 The blue spots on the outer edge of the wings are so much re- 

 duced that often two small flecks alone remain. The red cross- 

 band of the fore-wings is spread out. In the black, that is 

 somewhat brownish, red- brown shading appears near the base 

 of the wing. The large white spot at the anterior border of 

 the fore-wing and the neighboring five scattered white spots 

 show a reduction, and the latter may even disappear. In all 

 of these aspects the type approaches a variety from the Canary 

 Islands. The pupas were kept 172 hours at 37° C, then three 

 to four days at 24° C. 



The effect of cold on Vanessa atalanta is showm in Fig. 8. 

 The ground color of the upper surface is bluish black. The 

 white spots are larger, and the whole of the outer tip of the fore- 

 wing is lighter. The red cross-band is reduced and broken. 

 The under surface of both wings are much changed, as the 

 figures show. 



The influence of heat and of cold on Vanessa antiopa is shown 

 in Figs. I and 2. The effect of heat (Fig. i) is to make "dusty" 

 the brown ground color of the upper surface, especially on the 

 hind wing, that may become nearly black. The blue spots of the 

 marginal row are reduced to half their normal size and are more 

 violet in color. The characteristic yellow margin is dusted with 

 brown. The pupae had been kept 60 hours at 37° C, and then 

 for 12 days at 24° C. The influence of cold is shown in Fig. 2. 

 The blue spots are much larger, and the ground color of the 

 wings is darkened. The marginal yellow band is reduced and 

 richly dusted with black scales. The pupae had been kept for 

 44 days in an ice chest, and then for 15 to 19 days at normal 

 temperatures. Another individual produced by cold (29 to 34 

 days) is shown in Fig. 3. It approaches Vanessa polychloros, 

 Fig. 4, in a number of points, 



Fischer has obtained some very aberrant forms of Vanessa 

 antiopa by heat and by cold. Some of those produced by cold 

 are shown in Figs. 1-8 as seen from above, and in Figs. 9-1 1 

 as seen from below. The former set (Figs. 1-8) is arranged to 



