12 THE ENTOMOLOGIST. 
THE INTERMITTENT SCARCITY OF SOME SPECIES 
OF THE GENUS MELITH#A IN FRANCE. 
By H. Rownanp-Brown, M.A., F.E.S. 
Wririnec to me from Le Cannet, near Cannes, Mr. Charles 
Morris says: ‘‘ 1912 was a marvellous year at Fontainebleau for 
Melitzas of all species occurring in that locality, e.g. Melitea 
cinxia, M. didyma, M. phoebe, M. purthenie and M. athalia; but, 
although in September the ground was covered with thick webs 
of young larve hibernating in thousands, the following season 
(1913), when we visited the spot, there was no trace of any 
Melitzas at all. What had happened, no doubt, was this, they 
had all perished for want of sufficient food to bring them to 
maturity, and I had a striking proof the same year with cinaia 
in the garden on the lawn of the small house where we take 
rooms. Some larve having been brought to me for identification, 
on hearing where they had been found, I discovered black masses 
of half-fed cinzia larvee in little heaps every few feet, the whole 
of the plantain having been consumed to the root, stalks and all, 
and the larve reduced to starvation. I placed some hundreds 
of them in my cage, and planted a large tray full of the food 
plant, rearing about half the number, the rest being liberated 
before pupation. About fifty imagines emerged. Had the larve 
been left to themselves, almost all must have perished. I find 
they are cannibals, and also devour their pupe. Evidently the 
parent emergence was too prolific—hence a famine.” * 
Mr. Morris then cites as a parallel instance the case of Thais 
polyxena var. cassandra in a little valley near Le Cannet where 
the growth of Aristolochia is scanty. ‘‘ Every few years, when 
otherwise polyxena would increase enormously, there is insufficient 
food for the larve, and next season scarcely an imago of the 
species on the wing. I have noticed this to happen about once 
in four years; numbers of larve, and hardly a single perfect insect 
when the season for them arrives.” 
Mr. Wheeler, in his very interesting paper on ‘‘ The Genus 
Melitea’’ where he speculates on the liability of cinxia to 
become extinct, does not weigh as a contributory cause to disap- 
pearance, the possibilities set up by Mr. Morris’s observations. 
Yet a species once locally common, as we may suppose cinaia to 
have been in England, would be more affected by this seasonal 
over production than in countries where it is widespread and, 
therefore, to be replenished from near neighbourhoods where the 
same disastrous failure of the food plant has not occurred. There 
* Mr. Morris does not mention the presence of ichneumons, and judging 
from the high percentage of emergences, his experience in this respect 
confirms Mr. Wheeler’s observations on the comparative immunity of the 
species (cp. ‘ Proc. South London Ent. and Nat. Hist. Soc.,’ 1914-15, p. 11). 
