THE SMALL TORTOISESHELL. 69 



exposure to the action of ammonia. The black markings vary 

 in size, and sometimes those on the costal area are more or less 

 connected or even confluent (Fig. 22) ; a greater or lesser 

 amount of blackish suffusion on the hind wings (Fig. 23) 

 generally accompanies confluence of the costal spots on 

 fore wings. The two black spots between veins 2 and 4 

 occasionally enlarge and unite, or, on the other hand, they 

 decrease in size to vanishing point. Some specimens have 

 black scales between the second costal spot and the black 

 spot on the inner margin, and the space between these two 

 spots may be entirely covered with black and so form a 



central transverse band (var. polarts). A modification of this 

 form is shown on Plate 38, lower figure. The yellow patch 

 between the second and third costal black spots is some- 

 times continued right across the wings to the yellow spot on 

 the inner margin, and in this respect resembles an Indian form 

 of the species named ladakensis. Dwarf specimens result, in 

 most cases, when the caterpillars have fed on hop (Humulus) ; 

 at least, this is so in confinement. 



The egg is at first green, but after a time becomes tinted 

 with yellow and the ribs stand out clear and transparent. The 

 eggs are laid in a cluster on the under side of a terminal leaf 

 of a nettle plant in May and again in July. 



