58 



Mariana cuttings and also on i3each seedlings. Isolated colonies on 

 the original plum tree were also watched. 



In some colonies when members of the fifth generation reached 

 maturit}^ on May 8, winged individuals developed, Avhile in other 

 colonies the winged form did not appear until the sixth and seventh 

 generations were reached. Our field notes show that the winged 

 form appeared in south Georgia as early as April 18, and, indeed, 

 winged individuals Avere found in great numbers in Atlanta on a plum 

 tree that Avas not at first under observation as earh' as May 1. 



All forms that have been observed to the present date are partheno- 

 genetic. Only a small percentage of a colony would become winged, 

 but winged individuals have continued to develop in every generation 

 until the present date (August 14). 



After about twenty-four hours 

 from maturity the winged individ- 

 uals leave the colony and estab- 

 lish themselves, either singly or 

 in groups of two or three, upon 

 neighboring trees, where they feed 

 for several hours before giving birth 

 to young. The terminals of succu- 

 lent shoots were invariably selected, 

 and the peach seemed to be pre- 

 ferred to the plum; in fact, the 

 winged were never observed to 

 locate on the plum, although sev- 

 eral plum trees were growing on the 

 grounds. 



It was never observed that the 

 direct offspring of the winged form 

 developed wings, but some individ- 



FlG. 3.— Aphis n. sp: adult from winged 

 form, m.uch enlarged (from drawing fur- 

 nished by Scott). 



uals of the second and succeeding 

 generations usually do so. 



It was also observed that when a colony was kept reduced to a 

 small number of individuals no winged individuals would develop, 

 but when allowed to increase to considerable numbers some such 

 would always appear. 



On August 1-1 some of the colonies had been carried to the tenth 

 generation from the winged. 



In order to get further assurance that an old species was not under 

 observation, specimens were taken from one of the breeding numbers 

 and submitted to Mr. Pergande, who again identified the insect as a 

 new species of the genus Aphis. 



It is desired to carry this breeding work on until the true males and 

 females are secured before describing the species. 



Adalia hipunciaia frequented our breeding colonies in great num- 



