172 SPILOSOMA VCREA. 
colour, spotted with black ; on which account they 
have been named Ermine and Leopard moths. 
Like the tiger-moths, to which they are nearly re- 
lated, they are subject to great variety in their 
markings, even in the same species ; of the common 
British species, S. menthasfri, not fewer than eight 
well marked varieties have been described. 
The wings of the male of S. acrea expand about 
two inches, those of the female two inches three 
quarters. Head, thorax, and upper wings of the 
male cream-coloured, the surface of the latter with 
numerous small black spots, five of which are placed 
in a regular row along the anterior border, and six 
on the external one ; hinder wings entirely yellow, 
with a few black spots near the externa) edge and 
middle. The abdomen is yellow, with a row of 
black spots down the centre, and another on each 
side ; the apex cream-coloured. 
In the female all the wings are white, with nu- 
merous black spots, which are very variable in their 
distribution, but there is a marginal row on the 
hinder wings which does not exist in the other sex. 
The abdomen is coloured nearly as in the male ; eyes 
and antennae in both sexes black. 
The caterpillar is said to be white when young, ' 
and to become nearly black when full grown, a 
transition to two extremes which is not common 
even among a race of creatures subject to great 
variation in regard to colour. In its intermediate 
stages, the prevailing hue is reddish-brown. When 
it has attained the period of its growth at which we 
