126 Bulletin de la Société Royale Entomologique d'Egypte 
we obtain 5.7, which si only a little more than the 
general average. 
N° 125 paired a little before making the first egg- 
oase on August 4 th and again on the 7th; the ma!e 
was eaten on the 10th and no other male was sup¬ 
plied. The first two intervals are 6 and 4 , giving an 
average of 5 . I have already pointed out that the 6th 
and 7th egg-cases are really two parts of the same, 
but I should not like to affirm that the second copu¬ 
lation was the cause of this particular disturbance 
although it is interesting to note that taken in con¬ 
junction with the previous interval and considering 
the 6th and 7th as one egg-case, the average would 
be 4, which is what one would expect for the middle 
of August. 
N° 17 paired between the 4th of July and the 
laying of the first egg-case on the 10th. It paired again 
with the same male on the 16th and perhaps again 
before the 2nd of August when the male was eaten. 
’The 6th egg-case was made on the same day and the 
intervals from the 5 th to the 10th are 6, 2, 8, 3 , 1, 
with an average of 4, which again is what might be 
expected as the normal interval. 
Whether later observations confirm the explana¬ 
tion I have suggested, namely that copulation after 
oviposition has begun is the source of irregularity in 
egg-laying, or whether another explanation be found, 
one fact remains established:— in the case of ferti¬ 
lized females, Irregularities in the intervals between 
ovipositions compensate one another during the op¬ 
timum period for egg-laying. This is more cleariy 
brought out in table IX, 
