SEX-DETERMINATION OF HADROBRACON BREVICORNIS. 255 



males than in the progeny of those fraternities in which the sexes 

 were equal, but although this condition obtains the numbers are 

 too small and the exceptions too numerous to be conclusive. 

 Thus the progeny of F^, F 3 6 and F 3 8 had excess ot females but 

 produced equality of sexes, while the progeny of 9 No. I had 

 equality of sexes but produced excess of females. 



As mentioned earlier in the paper, virgin females gave only 

 male offspring. 



Twenty-six virgin females were isolated and produced 757 

 males. The fraternities consisted of 4 to 84 individuals. Eight 

 females that were with males produced 146 males and no females. 

 It is probable that they did not mate. 



TABLE II. 



OFFSPRING OF FEMALES, BEFORE AND AFTER MATING. 



Total from thirty-six virgin females 1,133 

 Total from sixty-one mated females (excluding those that were set with males 

 but produced only males) 683 cf cf , 918 9 9 . 



Table II. shows the progeny of ten females that were mated 

 late in life after they had produced several males. Seven of 

 these were mated to their own parthenogenetically produced 

 sons. In every case only males were produced before the mother 

 mated and nine of the mothers produced daughters after mating. 

 Virgin female F 4 i produced fifty-one males after being intro- 

 duced to a male. It is probable then that she did not mate. 



