S. A. Arendsen Hein 263 



11. The male and the female exhibit secondary sexual characters 

 which facilitate the separation of the sexes. 



12. The number of eggs produced by one female is very variable. 

 As a maximum 359 eggs were obtained from one individual. 



13. Also the duration of the egg-production varies very much. 

 In the normal condition it lasts two months. 



14. The duration of life of the female exceeds that of the male. In 

 a series of experiments the $ was found to survive the </" by about 

 51 days. 



15. The male mates with more than one female. It was established 

 as a fact that one male had copulated with 16 females. 



16. The mating of the beetles does not take place within 48 hours 

 after the pupal moult has been cast. 



17. The number of sterile eggs produced by a virgin $ is small, 

 presumably there may be only a few. Most females produce no eggs 

 without previous mating. 



18. Between the GB and OR beetles no morphological differences 

 can be observed ; the individual of the GB beetle, that has attained its 

 adult colour, is as a rule darker than that of the OR beetle. 



19. The BA beetle is a melanistic form. It dififers from the GB 

 and the OR beetle in : 



(a) That the beetle during the final coloration does not pass through 

 a stage of red brown, as the GB and OR beetles do. 



(b) That the abdomen, antennae and legs are coal black, whereas 

 these organs are red brown in the GB and OR beetles. 



20. It has been established that, besides some quantitative variations, 

 the yellow and red colour of the eyes and some forms of reduction of 

 the number of tarsal and antennal segments, are based on hereditary 

 factors. The yellow eye-colour has a sex-limited descent, but the red 

 appears to be not sex-limited. Strains can be reared which, with respect 

 to these abnormalities, breed true. 



Utrecht, Febritary 1920. 



