36 
tuted as a differential character by Mr. Fenn (Ent. Bee., i., p. 276), but 
which is also sometimes variable ; at any rate truncata seems incapable 
of throwing those acute prolongations or teeth which are normal in 
immanatci, while on the other hand its minute teeth at the costal end 
are most rarely reproduced in European immanatci. Here also the 
important biological fact is emphasised, which seems first to 
have been made public by Edleston ( Zool . xxi., p. 8784), that 
C. truncata is normally double-brooded, but in any event hibernates as 
a larva, while C. immanata is single-brooded and hibernates as an cipj, 
as was indeed suspected by Hellins, earlier ( IVeeld. Ent., i., p. 20). So 
far as subsequent history has revealed, there is no variability in this 
hibernating habit,* and a moment’s thought will show that it is in no 
way analogous to the occasional abnormal hibernation of Folia 
.ranthomista, etc. One may obtain eggs from C. truncata in May or 
June, or August or September, and they will hatch in about a fort¬ 
night, more or less ; but eggs of C. immanata laid between these two 
periods, or at the same time as early second-brood truncata (August) will 
wait until the following March, or thereabouts. Surely this, apart 
from all other considerations, should have proved fatal to the theory 
of “ forms of one species.” In Scotland, truncata is often only single- 
brooded, appears a little earlier in the season than immanata, but 
evidently keeps true to its hibernating habit. I cannot attach much 
importance to a rather muddled note by Mr. W. Reid (Ent. Bee., i., p. 
278). Edleston and Hellins agree that the newly-hatched larvte of 
truncata are whitish, those of immanata yellow. 
Hellins’ article in the “Entomologist’s Monthly Magazine” begins 
with details of dates, which I need not quote. He next records the 
interesting fact that: “ Whilst, as Mr. Doubleday has often proved, 
two or three varieties of russata appeared in the same brood, for 
example, saturata and perfuscata from eggs of centum-notata, and again, 
centum-notata from eggs of comma-notata i; on the other hand, neither 
the type immanata, nor its variety marmorata, produced any offspring 
differing in depth of colour from themselves.” But he fully expects 
subsequent experience in breeding will prove to the hilt Doubleday’s 
contention that they belong to one species, and that in the group there 
are “ tiro, no more and no less than two species.” His detailed descrip¬ 
tions of eggs and larvee bring out the following points by means of 
italics ; the egg of truncata is very pale ochreous, that of immanata 
yellowish, sometimes lightish red ; the fullfed larva of the former has 
* I venture to refer Gregson’s note on “ Cidaria immanata ” (T Veekl. Ent., 
i., p. 45) to truncata. He had “ repeatedly bred it from the egg ” and “found 
them hatch very soon after being laid, when kept in a warm room.” 
f From the account in Sepp’s “ Nederlandsche Insekten,” iv., pp. 23-24, it 
appears that Heer F. C. Decourt, of Dordrecht, obtained all the three principal 
forms, and in rather extreme phases, from the same batch of eggs, and they are 
well figured on pi. viii., figs. 9 (white banded), 10 (tawny banded), and 11 (black 
banded). On the other hand, it not infrequently happens that an entire brood 
follows one form with remarkable constancy, as in the case of a light batch bred 
by my friend, Mr. J. E. Gardner, “smoky ” ones bred by Mr. Barrett from West 
Wickham (Ent., xxxii., p. 310), by Messrs. W. Smith, and G. F. Mathew from 
Lamlash (Arran), and by myself from Tunbridge Wells, a melanic one by Mr. 
Oliver, of Wolverhampton, and apparently the light brood figured on pi. vii., of the 
cited volume by Sepp. 
xviii. 
