Zoology. — “The interrelations of the species belonging to the 
genus Saturnia, judged by the, colour-pattern of their wings.” 
By Prof. J. F. van BEMMELEN. 
(Communicated in the meeting of May 3, 1919). 
In his handbook of Palaearctie Macrolepidoptera STANDEFUSS says 
on p. 106, at the end of his passage on the relative age of the three 
species Saturnia spini, pavonia and pyri: “If-we exclusively | 
paid attention to the imagines, much might be said in favour of 
the opinion, that spini is older than pavonia. For both sexes of 
spini, aud likewise those of the new species from Kasikoparan (S. 
Cephalariae Ch.) discovered as late as 1882, possess a remar- 
kably uniform type. From this type the male of S. pavonia 
sharply deviates, this species thereby appearing as recently changed 
in its imaginal dress. But as to the question if we should place the 
origin of Sat. pyri before the evolution of these minor forms or 
after it, the imago of this latter species does not seem fit to allow - 
of a really certain conclusion. 
In regard to the caterpillar- and pupal-stage, however, things are 
different. For these it can be clearly proved that S.spini, pavonia 
and pyri form in many instances three different degrees of protec- 
tive resemblance against certain hostile factors of the outer world. 
In this seale everywhere spini occupies the lowest, pyri the highest 
degree. Keeping in view the excessively near relation and the 
great similarity of biological conditions between the three species, 
we are obliged to assume that spini came into existence before 
pavonia, and pavonia before pyri, or, using the scientific ex- 
pression for these relations: that phylogenetically spini is the oldest, 
pavonia a younger, pyri the youngest form. For it evidently would 
be absurd to assume that in a series of so intimately related forms, 
the more perfect living being should have originated at an earlier 
date than the less perfect one”. 
These considerations of Sranpruss induced me to compare the 
wing-markings of Saturnine-species, as well among themselves as 
with those of related genera, to see if this line of investigation did 
or did not lead to corresponding results as the inspection of the 
caterpillars, ) 
