41 



yapce in British North America, stated that many specimens 

 showed a marked increase in the depth of the yellow colora- 

 tion of the under side. He thought that the insect's 

 constitution must be very hardy to withstand extremes of 

 temperature, such as 90° of frost and 138° heat. There was 

 apparently a continuous brood throughout the Canadian 

 spring and summer. Mr. Tutt remarked on the oscillation 

 in abundance and rarity of the last species. There had 

 evidently been a struggle between this species and a closely 

 allied native species, Pieris oleracea, in which P. rapes had 

 finally shown itself capable of holding its own. It was 

 thought that most likely as the two species were closely 

 allied they had interbred. The other species concerned 

 was now most difficult to obtain. 



Mr. Tutt exhibited for Mr. Merrifield a number of bred 

 specimens, the outcome of his recent experiments. 



1. Two bred specimens of Aglais (Vanessa) urticce, var. 

 ichnusa, from S. Europe, a captured ordinary form for 

 comparison. The two specimens showed an extreme de- 

 velopment of the red both in amount and depth ; while, 

 on the other hand, the black was deficient. 



2. Several specimens of the same species which had been 

 subjected to different temperatures during pupal develop- 

 ment. 



{a) High temperature. The specimens showed a strong 

 tendency towards the ichnusa form. 



(6) Low temperature. These specimens showed an op- 

 posite tendency, — the red narrowed, the black increased in 

 amount and depth ; the scaling was weak, and the fore-wings 

 were decidedly narrower. 



3. Several specimens of Pyrameis atalanta. The colour 

 changes showed that in this species the cooling did not 

 intensify the dark markings, but increased the white, while 

 at the same time the red was restricted in area. An in- 

 creased temperature produced just the opposite result. In 

 two specimens, one of the cooled and one of the heated, both 

 females, an extra white spot was developed below the red 

 band. 



4. Eiivanessa antiopa, one normal, and two which had 

 developed under a low temperature. This experiment 

 suggested an exact parallel to the case of A. urticce. The 

 dark markings had spread, but were not so rich. The blue 

 was much increased in amount and richness. The border 

 was very considerably studded with dusky scales. Even the 

 shape had been considerably modified, the unnatural con- 



