No. 398.] THE GENITAL ORGANS OF ZAITHA. 121 
ries in December (Fig. A) have much the appearance of testes. 
Each ovariole is proximally attenuated (3), then enlarges (4), 
and distally is continued as a narrow tube (5). Perhaps, as in 
the testicle, the portion marked 5 should be regarded as an ovi- 
duct rather than a portion of an ovariole (follicle) ; in this case 
the portion marked 6 would be the undivided portion of the 
oviduct. Terminally is the vagina (7). (Fig. A represents all 
five ovarioles of the left ovary, but for the sake of clearness, 
only three ovarioles of the right ovary are shown; 8, the 
rectum ; 9, the terminal ventral plate of the abdomen; 10, the 
outline of the posterior edge of the abdomen.) Proximally, 
the two ovaries are connected together by a fibrous thread (2, 
thread of Müller); and this thread is connected by another 
thread (1) to the pericardial wall The dimensions in Fig. B 
Should be doubled to be in the same scale of drawing as 
Fig. A. ; 
From this description it will be seen that the female genital 
organs of Zaitha and Belostoma are quite similar, but that the 
male organs are very different. In Belostoma each testis con- 
sists of a single convoluted follicle; in Zaitha, of five distinct 
and well-separated, nearly straight follicles. Léon Dufour 
(Recherches anatomiques et physiologiques sur les Hémiptores) has 
not only given a most admirable description of the genitalia of 
Hemiptera, but also has insisted on their high value in taxonomy. 
Their worth seems to me also to be of great importance for 
classification. Consequently, when Belostoma and Zaitha differ 
so markedly in the structure of their male reproductive organs, 
we must conclude that these genera are by no means so closely 
related as they have been assumed to be; that in fact it 
might be proper to separate them into different families. 
Zaitha shows more relationship to Nepa in these structural 
characters than to Belostoma. 
UNIVERSITY OF PENNSYLVANIA, PHILADELPHIA. 
