57 
series to be very sure of this. It is noticeable what a much larger 
proportion of the males than of the females have lost this spot, and it 
is also apparent that the spots are generally smaller on the males than 
the females. The large amount of variation and asymmetry in the 
spotting, points, I think, to the rather unusual strength of this feature 
in the brood being an atavistic character, and further to the probability 
of the spots in .S', urticae being a survival of no present use, if not 
actually harmful to the species. 
General remarks.— The wide range of variation in the broods of 
M. castrensis and .S’, urticae is in marked contrast to the constancy of 
the specimens in those of A. putris and <umbratica. From the stand¬ 
point of natural selection, this variation suggests a great difference in 
the habits and methods of protection between the former and the 
latter. A. putris and U. umbratica are doubtless protected by very 
specialised development of coloration and pattern ; that of the former 
giving it a wonderful resemblance to a dead and broken twig. In 
captivity it folds its wings closely against its body after the fashion of 
Vhalcra bucephala. I have never found it resting under natural 
conditions, but should expect it to rest in the lower portion of a hedge¬ 
row or under bushes where dried and broken twigs are plentiful. 
C. umbratica presents a beautiful example of protective coloration 
Avhen resting on unpainted wood work, such as a split oak fence or a 
gate post, but it seems hardly likely that its scheme of coloration was 
evolved since these comparatively modern resting-places have been 
available. Probably its natural resting-place would be the dead and 
dried stems of burdocks, mulleins, thistles, Ac., on which it would be 
equally wel 1 if not more perfectly protected. 
The imaginal life of M. caxtrcmis would seem to consist only of 
pairing and oviposition, and under normal conditions is probably not 
prolonged for more than three or four days, so that its need of protective 
coloration is certainly less than with the above mentioned Noctuid 
moths. Its habits (in captivity) suggest that it hides low down among 
the herbage, or perhaps the drift rubbish of the saltings. In any case 
its resting-places are likely to be varied and the range of coloration in 
individuals would give the species as a whole, a better chance of 
escape. In captivity, when resting on the dried sallow and willow 
leaves, among which the cocoons were spun, it was very far from being 
a conspicuous object. 
As to .S. urticae I am not aware of its resting-habits. The colora¬ 
tion of the allied -S. menthastri and its freely exposed resting-places, 
suggest that it is a nauseous species, as I believe a good many of the 
Arctiids are, but the tendency of development in N. urticae towards 
pure white, suggests that it may obtain some sort of protection by its 
resemblance to a feather, for although many fen and marsh species are 
protected by their pale coloration, the white of A. urticae is too 
aggressively pure to Avar rant the assumption that it could pass 
unnoticed among even such pallid surroundings as Avitherel reeds. On 
the other hand, the Avhite coloration of this moth may still have a 
Avarning significance to bats and night-flying birds. The Avhite 
Liparids, Porthesia chnjxorrlutea and similis are, in all probability, 
protected by the irritating larval hairs Avhich become entangled in the 
anal tuft on emergence, Avhile T.cucoma rnlici *• is able to exude a bright 
green nauseous (?) fluid from two orifices in the thorax. 
