THE GENUS ENNOMOS (SENS. STR.). 57 
similar numbers of zygotes SS and SQ, a prediction exactly in 
accordance with the actual result, except for the slight effect of 
the colour factor in certain cases—a factor which, in other 
instances, can be demonstrated to act independently of the whole 
‘block ” of characters. : 
(p) The Problem ofthe Gynandromorph.—The characters of the 
gynandromorph give usa very peculiar problem to discuss, more 
particularly in view of certain recent developments in theoretical 
zoology. On dissection of this specimen, as was pointed out, 
only certain secondary sexual characters were found to be female, 
the primary organs being wholly male. Now, according to the 
“hormone” theory, the development of the secondary sexual 
characters is stimulated by the secretion and subsequent dis- 
tribution through the body of certain substances called hormones, 
these hormones being formed either in the testes or ovaries or in 
the interstitial tissues of these organs. As the present specimen 
has only testes, the hormone, developed and passed into the soma 
in the early life of the insect, ought to have caused the develop- 
ment, in all parts of the body, of solely male characters ; yet we 
see that, except for the colour and the primary sexual characters, 
the right side is wholly female. It is clear, therefore, that the 
hormone theory does not account in toto for secondary sexual 
characters. It is not here denied that experimental data prove 
that this is one of the causes; it is simply asserted that there 
must be some inherent qualities in the tissues of the soma to 
allow of their development independent of any secretions of the 
primary organs. 
As noted above, whilst the majority of the characters of the 
right side were female, the colour was wholly male; clearly the 
colour has acted as a unit character independent of the others, 
as was indicated above. This isa further proof of the validity 
of the Mendelian concept of a unit character and also of the 
possibility of coupling, i.e. the remaining characters acting 
together. 
(x) The Asymmetrical Specimen and its Problems.—We have 
here an example of an insect displaying hybrid characters only 
on one side, the other side being typical of the pure male parent. 
It seems clear that we are concerned with some kind of double 
fertilisation. That the phenomenon cannot be produced as the 
result of an ovum with two nuclei is certain, for then we ought 
to have had quercinaria characters on both sides, and we are 
therefore forced to the conclusion that the influence of the male 
has in some way caused the anomalous creature to be developed. 
Cases are well known of the passage of two spermatozoa into one 
ovum, but normally the second spermatozoon degenerates and 
fails to effect the embryo. Here, however, the whole of the 
circumstances are abnormal; we are dealing with the fertilisa- 
tion of an ovum by foreign sperm. Probably, then, two sperma- 
