S. A. Arendsen Hein 245 



The shortest duration of life of the </ was 39 days 

 „ longest „ „ ^ „ 113 „ 



„ shortest „ „ $ „ 89 „ 



„ longest „ „ ? „ 132 „ 



After the death of the (/ , the $ goes on regularly depositing ferti- 

 lized eggs. As an extreme case I observed that a female deposited 

 2 fertilized eggs, 63 days after the death of the (/. As a widow she 

 had produced as many as 95 eggs in those 63 days. So it is clear, that 

 once the $ has copulated, she is not fit for cross-breeding experiments 

 with another j/", supposing she copulated more than once. 



For this, and other reasons, it was of great importance for these 

 researches that I should be able to determine the sex of the beetles 

 immediately after the throwing off their pupal skin. 



4. The Copulation. 



In these experiments there occurred circumstances in which it was 

 desirable to know whether a cT copulates with more than one ?, in 

 other words whether a (/ brought together simultaneously with a number 

 of females fertilizes more than one of them. And also conversely : the 

 question whether the ^ copulates more than once was of some interest. 



For the first case the course of the experiment was simple. In each 

 of a series of five pots one </ and one $ were brought together. As soon 

 as eggs appeared, they were gathered, and the ^ replaced by another 

 virgin $ ; then a following egg harvest was awaited, and the second 

 replaced by a third ? ; and so on. The eggs gathered of each copulation 

 were kept, till they were hatched to ascertain the fact that they had been 

 fertilized. The results of this investigation are given in the table on 

 page 246. 



Of the five male beetles No. 2 died untimely. Of the four othere 

 No. 1 copulated with 16 females before he was killed by the 17th 

 female. Male No. 3 copulated with 11 females; No. 4 and No. 5 with 

 10 females. Three of the males were eaten (Nos. 1, 3 and No. 5); 

 whether the two others died a natural death could not be made out ; no 

 mutilation or traces of it were observed. 



An investigation into the number of copulations of the female is 

 much more elaborate and takes some years, because in general no indi- 

 cations of repeated copulation can be obtained until some succeeding 

 generations have been kept. 



She had to be crossed successi^fely with males of different here- 

 ditary characters, and the new characters at our disposal were all reces- 



17—2 



