Permutations of Sex 



Another, between the 9th and 27th of 

 May, stocked six Snail-shells with a family of 

 thirteen, including ten males and three fe- 

 males. The places occupied by the latter in 

 the series were numbers 3, 4 and 5. 



A third, between the 2nd and 29th of May, 

 colonized eleven Snail-shells, a prodigious 

 task. This industrious one was also exceed- 

 ingly prolific. She supplied me with a family 

 of twenty-six, the largest which I have ever 

 obtained from one Osmia. Well, this ab- 

 normal progeny consisted of twenty-five males 

 and one female, one alone, occupying place 



17- 



There is no need to go on, after this mag- 

 nificent example, especially as the other series 

 would all, without exception, give us the same 

 result. Two facts are immediately obvious. 

 The Osmia is able to reverse the order of 

 her laying and to start with a more or less 

 long series of males before producing any fe- 

 males. In the first case, the first female ap- 

 pears as number 7; in the third, as number 

 17. There is something better still; and this 

 is the proposition which I was particularly 

 anxious to prove: the female sex can be per- 

 muted with the male sex and can be permuted 



177 



