38 
In both cases there can be no question of a simple printing-over 
as Poutron suggested. Van BEMMELEN's figures of the pupae of P. bras- 
sicae and napi, as well as those of Euchloe cardamines and Aporia 
crataegi, which two last do not any more than the two former 
possess a primitive design during the last larval stage, give satisfac- 
tory evidence that the pupal pattern in all four is identical. He 
likewise proved that a similar system of markings was to be seen 
on the body of the imago during its development inside the pupal 
sheath 
A remarkable fact in this connection is the occurrence of a pig- 
mented spot on the abdomen, in the position where a dorsolateral 
seta might be looked for. This in my opinion, might be explained 
in two ways. 
Hither the dorsolateral seta is a primary one, which has usually 
vanished, but has remained on the thoracic segments and on the pupa. 
Or, the dorsolateral seta is of a more recent origin than other 
primary setae and so manifests itself at a later stage on the abdo- 
minal segments than on the thoracic, as these latter are more ad- 
vanced in their evolution. If this explanation is right, the pupa must 
be regarded as more highly developed than the first larval instar 
as regards the colour-markings. 
The tirst assumption seems to me the more probable. 
In any case the pupal markings are less complicated than those 
of the last larval instar and so provide us with an excellent 
example of convergent evolution. 
The Hague, March 10, 1916. 
Anatomy. — “Some Observations on Periodic Nuclear Division in 
the Cat.” By Mrs. C. E. DROOGLERVER FORTUYN— VAN LEIDEN. 
(Communicated by Prof. J. Boeke) 
(Communicated in the meeting of March 25, 1916.) 
Introduction. After several authors had expressed their astonish- 
ment that so few mitoses occur in growing tissues, CaILD in 1904 *) 
and 1907 *) and Parrrrson in 1908 *) have tried to explain this by 
refuting, on account of their own cbservations, the generally accepted 
view that mitotic nuclear division would be the only normal one. 
Cuitp studied the most various tissues of animals of diverse 
1) Anatomischer Anzeiger. XXV. 
2) 7 : XXX. 
7} . - XXXII. 
