600 SIDNEY I. KORNHAUSER 
8. DISCUSSION 
In the arthropods transformation of various male sexual char- 
acteristics to corresponding female characteristics has been 
known and adequately described only in crustaceans infested 
with parasitic cirripeds. Giard in a series of papers and Smith 
more recently have identified themselves enduringly with this 
problem. Smith not only described the external changes of the 
hosts, but went into an analysis of the effects of the parasites 
on the hosts’ metabolism, using both histological and chemical 
methods of attacking the problem. He also opened up the field 
for a discussion as to the manner in which female characteristics 
are made to appear in the male. 
Early in the study of the effects of parasites on sexual char- 
acteristics, the term ‘castration parasitaire’ became associated 
with this phenomenon, chiefly through the work of Giard. This 
term leads one immediately to look upon the transformation as 
being due to castration effected by parasites. This association 
of castration with changes in sexual characteristics may be 
attributed to our knowledge of the important influence exerted 
by the gonads of vertebrates, and especially mammals, upon the 
development of the soma. Whether effected experimentally or 
by parasites, castration produces striking results in the higher 
animals. It is therefore natural, since such parasites as the 
rhizocephalans or in the case of Thelia, Aphelopus, generally 
cause the gonads of the host to undergo reduction or complete 
obliteration, that we should associate the somatic changes 
incurred with the loss of the testes or ovaries. Still at the 
present time there is no evidence in the work on arthropodsto 
support such an inference. It is therefore urged that the term 
‘castration parasitaire’ be set aside in considering the alterations 
induced by parasites on the sexual characteristics of arthropods 
There are several lines of evidence drawn from our knowledge of 
the crustacea and insects to support this contention. 
That the gonads of insects do not produce hormones which 
shape the development of the secondary sexual characteristics 
is shown by the numerous cases of successful experimental 
castration of immature individuals, followed by development 
