114 



THE SPRIXG GRAIN- APHIS OR ' ' GREEN BUG. ' ' 



The male refused to mate with an}- more females after the twelfth. 

 Table XIII shows the results of these observations: 



Table XIII. — Offspring produced as the result of mating one male Aphidius with 12 



females. 





Female 



Offspring. 



Female, 

 cage No. — 



mated ■with 

 male from 











cage No. — 



Males. 



Females. 



180 



180 



29 



55 



181 



180 



14 



33 



182 



180 



21 



30 



1S3 



180 



35 



41 



184 



180 



2 



8 



1S5 



180 











186 



180 



13 



30 



187 



180 



39 



25 



1SS 



180 



1 







189 



180 



50 







190 



180 



8 



9 



191 



180 



26 



16 



From these data it appears that all of the eggs from the last few 

 females were not fertilized, as Mr. Kelly finds that females predom- 

 inate when the eggs are properly fertilized. Table XIV illustrates 

 this latter point. 



Table XIV. — Offspring of Aphidius produced from eggs properly fertilized. 





Offspring. 



Cage No.— 











Males. 



Females. 



197 



39 



67 



297 



15 



20 



299 



13 



33 



300 



24 



40 



302 



20 



34 



304 



16 



50 



306 



47 



12 



333 



115 



15 



403 



26 



41 



404 



3S 



93 



405 

 Total . . 



26 



44 



379 



429 



1 These two females were apparently unfertilized, although they were supposed to have mated, as they 

 give about the same results as some of the unmated females. If these two be eliminated it will be seen that 

 the females are far in excess of the males. 



PARTHENOGENESIS. 



In all of the studies of parthenogenesis care was taken to preserve 

 both parents and offspring, the individuals of each family or brood 

 being preserved and kept entirely separate for future systematic 

 studies, which were later carried out by Mr. Yiereck. 



The first record of parthenogenesis of this species was published in 

 the Proceedings of the Entomological Society' of Washington, 1 by 

 the junior author, whose attention was first called to tins phenomenon 



1 Proc. Ent. Soc. Wash., vol. 10, Nos. 1-2, September 15, 190S, pp. 11-13. 



