1962] 
Roth and Stay - — Cockroaches 
i B s 
rarely. Nine females of Nauphoeta cinerea had eggs that developed 
parthenogenetically and in 8 individuals the eggs hatched; two un- 
mated females that developed from unfertilized eggs gave birth to 3 
nymphs (Roth and Willis, 1956). We have encountered only one 
case of parthenogenesis in Leucophaea (20 undeveloped eggs and 5 
well developed embryos with pigmented eyes in an ootheca 89 days 
after ovulation) and one in Byrsotria (2 well developed embryos, 55 
days after oviposition) ; Barth (personal communication) has reared 
a single adult female of Byrsotria that was produced parthenogenetic- 
ally. Only one unmated female of the bisexual strain of Pycnoscelus 
was found that had a developed embryo in one of the eggs of the 
ootheca (Roth and Willis, 1961). Parthenogenesis in false ovovivi- 
parous cockroaches depends upon ( 1 ) the ability of virgin females to 
mature their oocytes, ovulate, and form and retract the ootheca into 
the uterus, and (2) the capacity for unfertilized eggs to develop. 
Although parthenogenesis cannot occur unless the above requirements 
are met, the insects must first be capable of retracting the ootheca into 
the uterus for unless this occurs the eggs desiccate since the ootheca 
does not prevent water loss in cockroaches that incubate their eggs 
internally (Roth and Willis, 1955). 
No experiments were performed on the species, in this study, to 
determine the mechanism of stimulation during mating. However, in 
Leucophaea (Engelmann, i960) and Diploptera (Engelmann, 1959, 
i960; Roth and Stay, 1961) it is a mechanical stimulus that activates 
the corpora allata and it is probably similar in Pycnoscelus (bisexual 
strain), Nauphoeta , and Blaberus. 
Food intake and maturation of the oocytes 
Food intake stimulates maturation of the oocytes in Leucophaea 
(Scharrer, 1946; Johansson, 1955; Engelmann, i960) and Blattella 
germanica and B. vaga (Roth and Stay, 1962) but is unnecessary 
for oocyte development in Diploptera (Engelmann, i960; Roth and 
Stay, 1961 ) . The effect of starvation on oocyte development in several 
species used in this study was determined ; all females were isolated 
from food at emergence. 
Pycnoscelus surinamensis : Fifteen females of the parthenogenetic 
strain were starved without water. All oviposited in 1 4.1 ±0.4 days, 
which was about 1 day more than in unstarved females (table 1). 
Nine virgin females of the bisexual strain starved without water ovi- 
posited in 1 4.3 ±0.5 days, which was similar to unstarved individuals 
(cf. table 1). Food is unnecessary in both strains to activate the cor- 
pora allata or for maturation of the eggs for the first ovulation. 
