SEXUAL CHARACTERISTICS OF THELIA 537 
male digestive tract. Thus the somatic tissues of insects are 
clearly sexually differentiated, and this differentiation is inde- 
pendent of the gonads. It is, therefore, superfluous, according 
to the author, to speak of primary and secondary sexual differ- 
ences in the insects, for all differences are primary—those of the 
soma as well as those of the germ plasm. Geyer (713) extended 
the observations of Steche to other Lepidoptera and also to 
other orders of insects, including rapacious forms in which no 
color differences existed in the haemolymph. He also carried 
out extensive castrations, transplantation of gonads, and trans- 
fusion experiments. His results are in perfect agreement with 
those of Steche. Even where no color difference exists, a pre- 
cipitate is formed in bringing together the haemolymph of oppo- 
site sexes. This precipitate is often quite as dense as that 
formed by mixing the haemolymph of different species or genera. 
He also showed that, where color differences existed in the blood, 
it was not due to an enzyme in the male destructive to the color 
found in the female haemolymph, for in no case could the meta- 
chlorophyll be bleached by the addition of male haemolymph. 
These observations of Steche and Geyer would seem to indicate 
that a male soma would be unable to furnish the coloring matter 
or the complete protein requirements for ova transplanted into 
such a soma. An interesting question might also be raised in 
regard to the characteristics of the haemolymph in perfect 
lateral gynandromorphs of Lepidoptera, such as described by 
Toyoma (’05), and in which doubtless half of the cells of the 
digestive tube are male and the other half female. 
Turning now to Nature’s own experiments on sex, gynandro- 
morphs, we have a definite line of evidence in the insects and 
Crustacea supporting the independence of somatic development 
from gonad influence. A complete analysis of the individuals, 
including the description of the gonads as well as external char- 
acteristics, is to be sought for in a study of the biology of sex. 
Such a description is given by Wenke (’06), whose article ade- 
quately describes and illustrates the conditions found in his 
Argynnis gynandromorphs. A perfect lateral gynandromorph 
contained a single well-developed ovary which did not in the 
