192 
Psyche 
[December 
We have repeated these and performed additional experiments on 
the following species of cockroaches : 
Pycnoscelus surinamensis (parthenogenetic strain) : Some of the 
experiments on this species were briefly described elsewhere (Roth and 
Stay, 1959). The ootheca was removed from the uterus of each of 10 
females 1 to 16 days after oviposition and one-half of each ootheca 
was implanted into the body cavity of the donor female. Twenty-three 
days after the operation the oocytes ranged in length from 2.12 mm. 
to 3.19 mm. (x=2.70±o.io mm.) clearly larger than the oocytes 
of females that have been pregnant for 24 to 39 days which vary from 
0.59 to 0.66 mm. Implantation of uterine eggs into the abdomens of 
females that had their oothecae removed did not prevent subsequent 
growth of the oocytes. Two of the 10 females had oocytes that had 
practically matured and the oocytes of the remaining 8 females were 
approaching maturity (2.97 to 3.36 mm., cf. table 1) and undoubted- 
ly would have matured in about the time one would expect ovulation 
following removal of the ootheca (cf. fig. 10). One-half of young 
oothecae were implanted into the body cavities of 6 females one day 
old or less; after 11 days the oocytes were 2.65 to 3.14 mm. (x— 
2.91=1=0.10) in length. The oocytes of untreated 11-day old females 
averaged 2.93=1=0.06 mm. (N=io). These results show that uterine 
eggs when implanted into the abdomen of a recently emerged female 
have no effect on the initial development of the oocytes. Nor does 
implantation of uterine eggs into the abdomen of a female that had 
her ootheca removed inhibit subsequent development of the oocytes. 
The oothecae of 20 pregnant females were removed 13 to 25 days 
after ovulation and a wax “ootheca” about the size and shape of a 
normal ootheca was inserted into the uterus. Examined 20 to 37 days 
later all had small oocytes (fig. 13A) similar in size to those found in 
females that were pregnant for 36 to 52 days (table 3). However 
Explanation of figure 12 
Fig. 12A. Pycnoscelus surinamensis (parthenogenetic strain). Ootheca 
(upper) and ovaries (lower) of a female that had been pregnant 60 days 
and whose nerve cord was severed on the thirty-second day of pregnancy. 
When dissected 28 days after the operation, the embryos in the ootheca began 
to hatch. The oocytes in the ovary had matured but were being resorbed. 
(Note the abundant colleterial gland secretion [arrow]). Vertical line — 3 
mm. 
Fig. 12B, 12C. Blaherus craniifer. B. Mated female whose nerve cord was 
severed 26 days after oviposition. The ootheca (0) containing well developed 
embryos (note pigmented eyes) was being aborted 34 days after the operation. 
The oocytes (arrow) were 5.88 mm. long. C. Virgin female that had carried 
an odtheca with undeveloped eggs for 93 days (well beyond the normal gesta- 
tion period). The oocytes were 3.92 mm long. Vertical line — 5 mm. 
