182 THE ENTOMOLOGIST. 
101) that in England 7. biundularia is generally found in the 
same localities as 7’. crepuscularia, does he mean that the records 
can be considered satisfactory, or to imply that the two insects 
are merely varieties ? Again, when he says that 7’. biundularia 
is confined almost entirely to Germany and Britain, is not the 
answer obvious, that continental entomologists generally do not 
record it as a separate species? For it is strange indeed that an 
insect so widely distributed in Scotland and England should be 
so local in Europe. As for the difference in size, tint, and time 
of appearance, I believe it is entirely due to variation; and I 
have noticed that whole broods have often a common character 
of coloration. Some years ago I bred about twenty of the warm 
brown 7’. biundularia from eggs of one female, laid in the third 
week of May. And many instances might be named to show that 
moths, as they extend their range southward, undergo changes of 
colour and time of appearance, becoming in some cases double- 
brooded and smaller. Mr. Harrison’s practical remarks (Kntom. 
159) strongly confirm my own opinion that the double-brooded 
crepuscularia is an exclusively southern insect, which point 
might be tested at once, as the moth comes out from the middle 
to the end of July. The view, therefore, that I take at present 
is that we have only one species, varying immensely in shade and 
colour, and that in the south, where the insect emerges so early 
as March, we have a degenerate second brood, or half-brood, in 
July, but that in the north it is uniformly single-brooded. In 
the south, the early brightly-coloured variety (crepuscularia) 
which gives birth to the second brood, has been held to be a 
distinct species, merely as an opinion, and without any foundation 
in fact, by Doubleday and some of his disciples. Referring to 
Doubleday’s List (1873) I find three synonyms for biundularia. 
The first is ‘‘ biundularia, Esp. (prec. var.),” the second, 
“ crepuscularia, Haw (var. ver.),” and the third “ crepuscularia, 
var. Gn.” If I understand this aright, we have the overwhelm- 
ing authority of Esper, Haworth, and Guenée, for saying that 
T. crepuscularia and T’. biundularia are varieties only of one 
species, while Doubleday stands alone as the advocate of a 
second species. I should now like to recall attention to 
Doubleday’s own words, which I quoted last month (Hntom. 
161), from which it appears that, though his opinion was in 
favour of two species, he could not support it by a single fact. I 
