1919] Riickes: Male Genital System in Lepidoptera 193 



structure of Bonibyx mori Linn, is now a classic. From that 

 date onward we find little concerning the genital system till, 

 in 1815, Herold produced his paper on the metamorphosis of 

 Pieris brassicce Linn., including other systems besides the 

 reproductive. This paper formed the basis for subsequent 

 work on the genital tract for it discussed the peculiar migration 

 of the testes to a median plane and, there, complete fusion into 

 a spherical body. It has been proved that this condition is 

 by no means typical of all Lepidoptera, being representative 

 of only the higher Rhophalocera. From the time of Herold's 

 work till 1865 seems to be a more or less stagnant period for 

 work of this sort. In 1865 Bessels published a few observations. 

 From the morphological point of view the greatest contributions 

 have been given by Chlodkovsky (1880-1913). Though short, 

 these papers are thorough and explicit, explaining the evolution 

 of the Lepidopterous genital tracts and their genealogical 

 relationship to those of other orders. Since 1884, histological 

 and cytological methods, combined with a continued increase 

 of our knowledge of chromosomes and chromosome reduction, 

 have led to the production of a vast amount of work and a large 

 number of observations on all groups of insects. A great deal 

 of this work has been restricted to the study of the maturation 

 of sex cells, regardless of the structure and function of the 

 surrounding tissues. Those doing the most comprehensive 

 general studies since 1884 are LaValette St. George, Verson, 

 Blatter, Berlese, Toyama and at a recent date (1913) Zick. 

 The views and criticisms of these authors will be discussed as 

 their particular points come up. 



METHODS AND MATERIAL. 



As above stated the Saturniidae furnished the basis of the 

 following study, though they were by no means the only forms 

 observed. The following is a list of species that were used: 



LEPIDOPTERA. ORTHOPTERA. 



Philosamia cynthia Drury. Dissoteira Carolina Linn. 

 Samia cecropia Linn. 



Callosamia promethia Drury. hemiptera. 



Thelea polyphemus Cramer. Anasa tristis DeGeer. 



Pieris (Fontia) rapcB Linn. Euschistus fissilis Uhler. 



Anosia plexippus Linn. E. variolarius Stal. 



Vanessa antiopa Linn. Nezara viridula Stal. 



