536 SIDNEY I. KORNHAUSER 
the gonads nor on hormones from the gonads. In more recent 
experiments Kopeé (’13 a) removed the imaginal disc of the left 
antenna from larvae which were castrated and into which gonads 
of the opposite sex were grafted. The regeneration of the 
antenna supported his former conclusions as to the independence 
of the soma, in that most of the antennae were normal in form 
and also showed their characteristic coloration—light in, the 
male and dark in the female. A few females developed light 
antennae, and Kammerer (713) attacked the conclusions of 
Kopeé, using these individuals for hisargument. Kopeé (713 b), 
by a series of check experiments, successfully answered Kam- 
merer’s objections by showing that in control females, not cas- 
trated, the regenerated antenna at times were light instead of 
dark. This condition is, therefore, not due to the absence of the 
normal gonad, but doubtlessly is caused by a trophic effect 
brought about by the operation. 
Another interesting and instructive line of work throwing 
light on the physiology of the sexes in the insects is that of Steche 
(12) and of Geyer (’13), who experimented with the haemo- 
lymph of various insects, mainly Lepidoptera. Steche noted 
that the haemolymph of male larvae of Lymantria dispar was 
yellow, that of the females green. The yellow pigment was 
shown to be xanthophyll, the green pigment a metachlorophyll 
formed from the leaves eaten by the caterpillars. Besides this 
color difference, there are protein differences between the sexes, 
shown by bringing together in a watch-glass the haemolymph of 
male and female larvae. At contact there was thrown down a 
‘veil-like’ precipitate. The stiffening of larvae into which for- 
eign haemolymph is injected may be explained by the formation 
of this precipitate. The sexual differences in color and protein 
content of the blood were shown to be independent of the gonads, 
for they remained unaltered in castrated individuals and cast- 
rated individuals with implanted gonads of the opposite sex. 
Steche attributes these sexual differences to the somatic cells 
which produce the haemolymph; thus, cells of the female diges- 
tive tract allow the chlorophyll to pass through quite unchanged, 
whereas only the xanthophyll passes through the cells of the 
