1955] 
Roth and Willis — Diploptera dytiscoides 
61 
The active male follows the female and palpates her body 
or genital region. He then partly raises and flutters his 
wings, turns his terminal abdominal segments toward the 
female, pushes backward under her and grasps her geni- 
talia. Once they are hooked together, the male swings 
around into the typical opposed position with his head 180° 
from the female’s. Newly emerged, teneral females are 
very attractive to, and are courted by, older males ; 2 males 
were attracted to a female that was only partly out of its 
last nymphal skin and went through weak courting move- 
ments. Surprisingly, these young females mate normally 
(fig. 14) and in laboratory cultures the mating of teneral 
females is a common occurrence. According to Hagan 
(1951, p. 320), sexual maturity in Diploptera “. . . follows 
physical maturity rather promptly, if the presence of well 
developed follicles in the last nymphal instar is any cri- 
terion.” Teneral females have been seen in copula before 
their wings had become fully extended; examination of 
one such female, after she had been in copula for more 
than an hour and had separated from the male, showed 
that she had received a spermatophore (fig. 15). Another 
teneral female, isolated while still in copula, separated 
from the male about 30 minutes after isolation. Sixty- 
seven days later, she give birth to 13 nymphs ; temperature 
and humidity were uncontrolled during the gestation period. 
We have observed four females forming oothecae. When 
the first female was seen, her terminal abdominal seg- 
ments were slightly separated. We anesthetized the insect 
and, upon microscopic examination, found about 6 eggs 
aligned vertically in a double row in her vestibule. After 
the female had recovered, she began pulsating movements, 
expanding and telescoping the end segments of her ab- 
domen. While viewing the posterior end of the female 
during these movements, we could see the first egg through 
a hand lens. None of the eggs protruded completely be- 
yond her body. About three hours after the female ceased 
her ovipositing motions, she was dissected. The ootheca, 
containing 10 eggs, had rotated (micropyles to the left) 
and it lay partly in the vestibule and partly in the brood sac. 
The other three females were discovered in the stock 
