6 
Psyche 
[March 
straight upward into the hsemocoelar space. The arrows 
indicate two steps in such a division of the ducts though 
only eight of the ten branches are visible in Plate 1, fig. 6. 
Adjacent to this gland another is found to the right of the 
median line. Its general course is the same in the atrium but 
its walls are thick and the lumen practically closed. It ap- 
pears in the hsemocoele as a stout column with an open lumen 
terminating in a calyx. From the latter arise approximately 
twenty very long, narrow, simple glandular tubes which coil 
around one another to form a compact knot. Its function is 
problematical. The six valvulae of the ovipositor are ap- 
proximately uniform in length yet no longer than the largest 
in B. germanica. They are, however, narrower and more 
delicate organs in D. dytiscoides than in the latter species. 
Two pairs are wide basally but taper distally to smoothly 
rounded tips. The valvulse of the third pair are very slender 
throughout their length. They are not illustrated. 
This, very briefly, is an outline of the female reproduc- 
tive system of Diploptera dytiscoides. While its component 
elements introduce no new structures which B. orientalis 
lacks, still some of them vary greatly from the latter species 
that maternal care and incubation may insure viviparity. 
Such changes include a reduction in the number of ovarioles 
with a consequent limitation of the offspring to be accom- 
modated at any one time. The lowered reproductive rate 
may also be associated closely with the apparent necessity 
for maternal nutrition of the embryos till hatching and 
birth, and the possible modification of the nature of the se- 
cretion from the right gland to furnish the required amount 
of nutriment. The ootheca, in turn, is reduced to a thin 
membrane which only partially envelops the egg mass and 
never turns brown upon contact with the products of the 
right gland as Pyror states is the case in oviparous species. 
Finally, the uterine portion of the genital chamber is defi- 
nitely established as an enormous incubatory receptacle for 
the embryos till hatching. The maintenance of oviparous 
parts and accessories in the viviparous production of off- 
spring once more recalls the old adage that “morphology is 
more conservative than physiology.” 
