178 
Psyche 
[December 
Of 47 virgin females that oviposited, only 1 1 retracted the ootheca 
into the uterus; the others dropped the egg cases while they were being 
formed. Virgin females frequently retain mature oocytes in their 
ovaries and the egg cases are incomplete (Engelmann, 1957a). 
Engelmann (i960) found that when females of Leucophaea had 
constant access to males, mating occurred when their oocytes averaged 
1 .08 ±0.0 1 mm. and none mated that had oocytes exceeding a size of 
1.46 mm. He concluded (i960, 1960a) that the corpus allatum hor- 
mone must be present in low titer for mating to occur, and as soon as 
a certain titer is surpassed, the females did not mate even with ready 
access to males. We exposed females of various ages to males for 
relatively brief periods (the longest time females were with males was 
2 days), and measured the oocytes of those that did and did not mate. 
One hundred and fifteen females between 14 and 52 days of age were 
mated and their oocytes varied in size as follows: 
1.08 mm. to 1.95 mm. (x= 1.43 ±0.02, N = 83 ) 
2.00 mm. to 2.97 mm. (x=2. 34+0.06, N=2i) 
3.1 1 mm. to 3.72 mm. (x=3.30±o.o8, N= 9) 
4.90 mm. to 5.88 mm. (x=5. 39^0.49, N= 2) 
A breakdown of the data into two age groups when mated was as 
follows : 
Size of oocytes (mm.) 
when mated 
Age (days) when mated and 
number mated 
14-25 
26-52 
1.08 - 1.95 
50 
33 
2.00 - 2.97 
8 
13 
3- 11 -3.72 
0 
9 
4.90 - 5.88 
0 
2 
As pointed out earlier our measurements are larger than Engel- 
mann’s because in our experiments the oocytes were dissected and 
measured in Ringer’s solution whereas he measured fixed oocytes. The 
majority of the females mated when their oocytes averaged i.43±0.02 
mm. This value probably corresponds to Engelmann’s mean of 1.08 
±0.01 mm. However, 28% of the females mated when their oocytes 
were more developed. Thirty-six females that failed to mate when 
exposed to males along with the above females that copulated had 
oocytes that ranged from 1.01 to 1.68 mm. (x= i.i9±0.02 mm.; 
N = 25) and 2.05 to 5.88 mm. (x=4. 54^=0.38 mm.; N=n). 
There was a slight but not very significant shortening of the inter- 
