al 
XXVIil 
In Scotland locally and in Ireland there is a well-marked 
variety (var. scotica) the female of which, though larger, bears 
a considerable resemblance to A. lapponica, which sometimes 
occurs with it. In Ireland there is a still more aberrant form, 
which I have named var. johnson. 
Very closely allied to this common species is the summer 
brood of the true trtmmerana of Kirby, while its spring brood 
has a male differing greatly from these in structure. 
That the true rosae either in its spring or summer. form 
should ever have been confused with the other two species is 
remarkable, for, apart from important structures, its com- 
paratively glatrous bedy gives it a most distinct superficial 
appearance. 
Saunders was in error in saying of his vosae that the dark 
varieties, were much more hairy than the red, for the black- 
bodied examples are just as bare as the reddest. 
In the series of both broods of rosae and of trimmerana the 
variation is well shown. The specimens are mostly from 
Devonshire, where highly coloured varieties of rosae are 
frequent. It will be noticed that in this part of England the 
spring specimens are nearly all highly coloured—though one 
male is the blackest I have ever seen—while in the summer 
brood dark-bodied examples are frequent. 
In trimmerana, on the contrary, the spring brood is on the 
whole darker in colour than the summer generation. 
The seasonal dimorphism in the two species is always well- 
marked in the males, but in the females individuals of either 
brood occur which are practically alike, although the majority 
are easily distinguished. 
AN EXAMPLE OF MARKED IRREGULARITY IN THE COLOUR- 
ADJUSTMENT OF A PIERIS RAPAE L., PUPA TO ITS SURROUND- 
inGs.—Prof. Pouttron exhibited, on behalf of Mr. A. H. 
Hamm, three pupae of P. rapae and one of P. brassicae, L., 
found within a few feet of one another on a wood fence which 
had been creosoted two or three times and was of a dark 
sepia colour. All the pupae were attached horizontally to the 
extreme top of the fence, immediately under a slightly 
projecting coping and therefore somewhat in shadow. The 
brassicae and one rapae were darkish pupae, the second rapae 
