1962] 
Roth and Stay — Cockroaches 
171 
Byrsotria fumigata: The effects of mating on oocyte development 
and oviposition in Byrsotria are shown in table 2 and figure 2. About 
50 percent of the virgin females failed to oviposit but of these 1 1 1 
females 61% had large well-developed oocytes that were degenerating 
or were being resorbed (fig. 14E). It is evident from figure 2 that 
after the thirty-fifth day of age the oocytes of many virgins degenerate 
although most of them may reach a length of 5 mm. or more. About 
16% of the virgins and about 10% of the mated females had small 
abnormally-shaped oocytes that were being resorbed. It is unlikely 
that lack of hormone is responsible for this type of abnormality since 
Barth (personal communication) has dissected pheromone-producing 
Byrsotria females which had small degenerating oocytes but accessory 
glands filled with secretion. 
In those females that mate, copulation has little, if any, effect on 
the growth rate of the oocytes (fig. 2). Mated females oviposited at 
26 to 41 days of age (x— 32.4+0.4 days; N ;=z 53) ; virgin females 
oviposited 26 to 44 days after emergence (x— 34.3 ±0.4 days; N = 
121). That there is little effect on the rate of growth resulting from 
mating is further borne out by the fact that the females oviposit at 
about the same age regardless of their age when mated. In our series 
the females were with males continuously until they mated; copula- 
tion occurred from 4 to 25 days after female emergence. The oocytes 
may vary considerably in size in females between these age limits 
(fig. 2). A female with large oocytes mated when 25 days old may 
ovulate 10 days later whereas one with small oocytes mated at 4 days 
of age may take 30 days to ovulate (fig. 3). This is quite different 
from the effect of mating in Leucophaea (Engelmann, i960) where 
the average interval between mating and oviposition is about the same 
regardless of the age of the female when mated (fig. 3) because the 
females tend to mate more readily when their oocytes reach a certain 
size (see below). Barth (1961) found that Byrsotria females begin 
to produce sex pheromone 10 to 30 days after the imaginal molt; 
however, recently (1962) he has found that some females may mate 
as early as 4 days after adult emergence. 
It seems that in Byrsotria mating (perhaps the presence of sperm 
in the spermathecae) serves as a stimulus to oviposition. This is 
indicated by the fact that the oocytes in many virgin females apparent- 
ly mature yet ovulation does not occur. The oocytes in virgin females 
at ovulation vary in length from 5.90 to 7.60 mm. (x=6.79±o.o6 ; 
N = 7). Although the mean ages at ovulation of mated and virgin 
females are very similar a breakdown of the data (fig. 4) shows that 
