136 Bulletin de la Société Royale Entomologique d'Egypte 
trace of development up to a certain stage, followed 
by a resting period until suitable conditions for fur¬ 
ther development arise, as in the case of the mulberry 
silk-worm for example. The study of the embryo- 
logical development of the Mantidae is very difficult, 
but if it could be carried out for a complete series the 
results would be of very great interest. 
If we compare table XI with table Mil, we find 
that the irregularities which occur in the latter cor¬ 
respond with a decrease in the length of the egg- 
stage where a normal increase would be expected. 
This is particularly evident in the case of N° 17 of 
which the 9th egg-case only took i 3 days to hatch. 
This egg-case was laid on the i 5 tli of August and the 
seven other egg-cases laid by fertilized females from 
the 1 3 th to the 18th of the same month all took 21 
days to hatch. When I tabularized these figures, I 
thought there must be a mistake, but the dates are 
recorded in seven different places as we bred six of 
the young which emerged from this egg-case; more¬ 
over the dates on which these six moulted for the 
first time make it impossible that there should have 
been a mistake. This egg-case is complete and 37 
young emerged; as the average for this female is 3 g, 
there is no reason to suppose that this egg-case is 
only a part of the previous or following one. Taking 
into consideration the other irregularities in the two 
tables, we must conclude that the same cause is 
responsible in both cases. As the figures for N° 16 and 
N° 88 are quite regular, further evidence is afforded 
in favour of the hypothesis that copulation after the 
first Opposition is the càuse. 
