Since then I have continued my investigations and published a 
paper containing the complete descriptions, the necessary illustrations 
and the list of literature as announced in my preliminary commu- 
nication. *) 
The remaining conclusions to which my further investigations have 
led me, may be summed up here: 
In the first place I have reconsidered the question as to the exact 
position of the “rudimentary stigma on the thoracic segments and 
have come to agree with Boas, who asserts the metathoracic stigma 
to have moved forward unto the intersegmental membrane between 
meta- and mesothorax, while the so called prothoracic stigma is in 
reality that of the mesothorax. 
A spot or some other mark of similar character, occurring in the 
place where the stigma might be expected, in reality corresponds to 
the rudiment of the wing. *) 
In the second place 1 devoted my attention to the number of the 
abdominal segments. 
In accordance with PourronN (1890) and Spunrr (1910) I think I 
am able to trace an eleventh abdominal segment in certain 
caterpillars, during their first instar; viz. in Flepialus hecta L., 
H. c.f. lupulinus L., Phalera bucephala L., Sphinx ligustri L., Pieris 
brassicae L. and P. napi L. 
The impossibility of demonstrating the presence of this eleventh 
segment in the majority of Lepidopterous larvae can be explained 
by taking into consideration the fact, that the moment of piercing 
of the egg-shell by different insects is not a fixed point in the course 
of development, but is dependent on the quantity of food-yolk ete. 
(Hennecuy 1904).. This explanation of the difference in the stage of 
development at the moment of emergence from the egg is the more 
probable, as CHaPMAN (1896) was able to show that a great deal of 
variety exists between the eggs of different Lepidoptera. *) 
Furthermore [ made a closer comparison between the markings 
of caterpillars with those of other insect-larvae. 
Dh A. Scurerseex, On the Setal Pattern of Caterpillars and Pupae, Inaug. 
Dissertation. Groningen. 20 Jan. 1917. This study is also published in: Onder- 
zoekingen verricht in het Zoölogisch Laboratorium der Rijks Universiteit te Gro- 
ningen. Part VI, and in Tijdschr. Ned. Dierk. Ver. 2e Ser. Vol XV. 
; 2) See also Paut Mayer, Jenaische Zeitschr. f. Naturw. 1876. 
3) This most accurate investigator writes me kindly that he has solved the 
problem of the difference between Packarp and myself in 1887. He was able to 
show that there are two races of Orgyia antiqua with a different number of 
moultings. The sexes of these races also were unequal in this respect. (03, © 
and 34, 25; Ent. Month. Mag.) 
74* 
