630 SIDNEY I. KORNHAUSER 
host, the parasitic larvae will be large and the assumption of the 
female characteristics pronounced; if deposited late, the altera- 
tions will be less marked. 
3. Of the changes in parasitized males none is more striking 
than the assumption of the pigmentation of the female. The 
character of the pigment and its distribution on the pronotum 
and head may duplicate exactly that of the female. 
4, Parasitized males increase in size, approaching but not 
reaching the size characteristic for female Thelia. Measure- 
ments show this increase in the pronota, wings, heads, legs, 
acrotergites, and abdomens. Thus all regions of the body are 
influenced and the amount of increase is correlated with the 
degree of alteration of the pigmentation, those with complete 
female coloration being largest. 
5. Parasitized female Thelia show no assumption of male 
pigmentation, nor do they change in size. 
6. Minute spines on the abdominal sclerites of parasitized 
males take on the arrangements characteristic of the female. 
The shape, pigmentation, and texture of the abdominal sclerites 
of parasitized males become female in character and various 
sclerites of the terminal somites associated with the genital 
appendages show considerable change toward the opposite sex. 
7. Parasitized individuals of both sexes sometimes show a 
weakened cuticula and a reduction of the melanic pigment. 
8. None of the changes described are due to a retention of 
nymphal characteristics. 
9. The genital appendages of parasitized males are not changed 
to those of the opposite sex. They are reduced in size and lose 
their specific characteristics, but retain the general form found 
in male Membracidae. Likewise, the gonapophyses of infected 
females show a similar decrease in size and a loss of specific 
characteristics, but retain the general form found in female 
membracids. 
10. The above (9) may be partly explained by a history of 
the gonapophyses. The genital appendages are laid down early 
in ontogeny and become clearly sexually differentiated in young 
nymphs. Thus the sexes may be easily ascertained by an 
