THE GENUS ENNOMOS (SENS. STR.). 55 
Ennomos hybrid goodwint = E. subsignaria 3 X HE. winnt &. 
This hybrid produced no female, but I would not suggest 
from this that no female can exist. Too few broods have been 
reared to allow of a definite statement that there is the total 
suppression of the female sex, such as occurred in my hybrids 
bulovect, denhami, etc. 
The imagines in this case showed a marked tendency to 
separate themselves into two groups—one closely resembling 
in colour, shape of wings, genitalia, etc., the species subsignaria, 
whilst the other was comprised of forms practically identical 
with males of winnt. What was noteworthy, too, was that these 
sections were numerically equal. These facts are discussed 
later. 
CoNcLUDING REMARKS. 
As a result of the above experiments, several very important 
observations stand pre-eminent, and their discussion has been 
reserved for treatment here. These are: 
(4) The very great vigour of the primary hybrids. 
(s) The apparent sterility of the primary hybrid male. 
(c) The definite division of each of the two secondary forms 
into two groups. 
(p) The points arising from the gynandromorphic individual. 
(x) The problem presented by the asymmetrical specimen. 
(r) The question of the secondary sexual characters. 
(a) Vigour of Primary Hybrids.—As was noted previously, the 
wing expanse of hybrid winni lay between the limits of 43-50 
mm., and, in this, it contrasts greatly with the measurements 
(88-42 mm.) of the diminutive subsignaria and those of the 
larger quercinaria (40-43 mm.). In fact, we have an increase 
of over 10 per cent. above the theoretical expectation or mean. 
This increase of size is significant, and agrees well with a similar 
increase noted in rearing Ithysia hyb. langet (= I. zonaria 3 X 
P. pomonaria ?) and its allied forms, and shows the great 
increase in constitutional vigour practically always observable 
in the rearing of insect hybrids. It confirms the general opinion 
that strange blood tends to increase the vigour of the race. 
(B) Sterility of the Male of the Primary Hybrid.—This sterility 
of the male of hybrid winni is in direct contradiction to the usual 
experience with hybrids; very rarely indeed do we find the 
female fertile when compared with the abundance of cases in 
which the male is functionally active, and, even then, a fertile 
female is accompanied by a fertile male. Why, then, does the 
male in this case appear sterile? Nay, the question becomes, 
when one considers the inability to secure fertile hybrid ova 
from subsignaria female, is it sterile? And the answer is in 
the negative. Let us examine the three cases. Winni 3 
X wimni @ yielded ova which failed to hatch, simply because, 
