110 Bulletin de la Société Royale Entomologique d'Egypte 
we have to consider, and in times of shortage we did 
not hesitate but used young individuals of the next 
generation as food for their older relatives. This factor 
may, therefore, be neglected. 
We have, as far as possible, excluded any here¬ 
ditary factors by studying the descendants of only one 
iemale. Their effects, if any, will appear in the varia¬ 
tions of individuals brought up under conditions as 
similar as we could make them. 
There is, however, one factor which cannot be 
disregarded. This is the effect of seasonal variation, 
especially in temperature. Although every stage can 
be obtained at any time iti the year, development 
during the winter months is almost entirely suspended 
and, although they do not hibernate in the strict 
sense of the term, the adults « live so slowly » (if I 
may be allowed to use this phrase which expresses 
their condition better than any other I can think of) 
that a month in winter is about equivalent to a day 
in July or August. This makes it very dangerous to 
compare the length of life of individuals from diffe¬ 
rent egg-cases. We have already drawn attention to 
this factor in the case of Sphodromantis bioculata, 
(1916.2) p. 92, and in that of Attacus ricini , the Eri 
Silk-worm, (1921) p. io 4 . 
Let us first consider a case of individual varia¬ 
tions, not due to any external cause or causes which 
could be observed. We tried to bring up 16 indivi¬ 
duals from egg-case N° VIII of Miomantis N° 3 . 
(N.B.—For the sake of brevity, this will be written as 
VIII. 3 . and so for other egg-cases, the Roman nu¬ 
meral indicating the number of the egg-case and the 
