540 SIDNEY I. KORNHAUSER 
x-chromosomes, whereas in the large egg all the chromosomes 
divide equationally and a female results. This idea does not 
assume that the x-chromosomes actually contains the deter- 
minants for the sexual characteristics, primary or secondary, but 
that they merely influence the development of these characteris- 
tics, which are in all probability borne by the autosomes. 
The second line of evidence is gained from breeding experi- 
ments. Harrison and Doncaster (14) have shown in Ithysia 
zonaria, in which the females alone are wingless, that the male 
of this moth (when crossed with the female of Lycia hirtaria 
winged in both sexes) transmits to his daughters a characteristic 
of the zonaria females, namely, small flightless wings, much 
smaller than those of their parents. Foot and Strobell (14, 
715, 717 a, 717 b) have crossed several species of Euschistus in 
which they have studied the inheritance of two ‘exclusively male 
characters.’ They have shown that the length of the intro- 
mittent organ and a black spot on the male genital segment may 
be transmitted through the female as well as through the male. 
What weight the term ‘exclusively male character’ carries is hard 
to gather from the papers, since, according to the interpretation 
of the authors, it includes characteristics at one time equivalent 
to primary sexual characteristics and at another time equivalent 
to sex-linked characteristics. The intromittent organ we would 
call a genital secondary sexual characteristic, whereas the spot 
we would call an extragenital secondary sexual characteristic or 
even a tertiary sexual characteristic. Foot and Strobell’s 
arguments against the chromosomal basis of heredity will be 
considered in the discussion. The facts of their breeding experi- 
ments show very nicely that, just as in birds and mammals, the 
female may transmit the male characteristics of her species in 
crosses. The determiners for these characters must, therefore, 
be present in her genetical make-up, although they were not 
expressed in her soma. 
We now come to the third line of evidence: the effect of para- 
sites on the sexual characteristics. There are three important 
papers dealing with the strepsipteran parasites of Hymenoptera. 
Perez (’86) describes and pictures the modifications in Andraena 
