то THE QUESTION OF ORIGIN OF THE PUPAL INSTAR 

 OF THE HOLOMETABOLOUS INSECTS 



К вопросу о позппкиовонии стадий куколки у насекомых с полным превращением 



Т'. J. А. NOVÄK аЫ К. SLAM А 



(Entomological Laboratory of Czechoslovak Academy of Sciences, 

 Praha, Czechoslovakia) 



A number of пелу discoveries concerning the morphology and physiology 

 of insect metamorphosis and particularly the metamorphosis hormones 

 in the recent years have lead to numerous attempts at a new conception 

 of the origin of complete metamorphosis and metamorjihosis in general. 

 Most of these authors for various reasons take a negatiл^e standpoint towards 

 the recognized theory of Berlese-Jezikov based exclusively on morphological 

 features лу111с11 was accepted almost generally several decades ago. The papers 

 by Hinton (1948 a. o.), Zachvatkin (1953 a. o.), Snodgrass (1954), Wigg- 

 lesAvorth (1954), Karpinski (1954) and .Sarov (195(3) may be remembered 

 as the most outstanding of this category. 



On the other hand the authors, in the sense of previous papers by Novak 

 (1951, 1955, 1956 etc.), consider the new discoveries a remarkable confirm- 

 ation of the main suppositions of Berlese (1913 a. o.) and Jezikov (1936, 

 1939 etc.). Novak's so called gradient-factor conception of insect metamor- 

 phosis suggests an idea of the origin of pupal instar which can be briefly 

 characterized by the folloлving principles: 



1. The development of holometabola passes the same morphogenetic 

 stages and in the same succession as the development of heterometabola with 

 the only difference in function and ecological accomodation of the respec- 

 tive instars which, of course, is secondary from the phylogenetic point of vieлv. 



2. The complete metamorphosis characterized by internal position of the 

 imaginai buds and intermetamorphosis moulting was developed from the 

 complete metamorphosis through the intensified and prolonged effects of the 

 juvenile hormone (JH). 



3. The origin of pupal moulting, i. e. moulting in the metamorphosis 

 period (in absence of JH) preceded phylogenetically the origin of an internal 

 position of the imaginai buds, i. e. the origin of the imaginai discs. The typical 

 state of immobility accompanying the pupal instar and characteristic for the 

 great majority of pupae Avas doubtlessly developed much later. A similar 

 situation Avas demonstrated as early as 1924 by Imms and exists in several 

 instances even in the heterometabola, e. g. in nymphs of some termite species, 



j Sympos. Evolutio Insoctorum 65 



