OF WASHINGTON, VOLUME XVII, 1915 45 



Chermesinse and of Ph. vastatrix, and the intermediate sexuparse 

 of the other Phylloxera. The first he classes simply as abnor- 

 malities, forms intermediate between types with diverse modes 

 of reproduction, while the second would constitute a type to 

 themselves, a true wingless form of sexuparse, or one with the 

 wings reduced. 



Dr. Foa fails to agree with Bonier, first, because there exist 

 in certain forms, alate virginoparse and one would suppose that 

 the intermediate virginoparse would group with these, like the 

 sexuparse with the alate sexuparse; secondly, because the sepa- 

 ration between virginoparse and sexuparse is not absolute, from 

 the fact that some nymphs can become virginopara or sexu- 

 para, because virginosexuparous forms exist. She further states 

 that if the intermediate forms of the grape Phylloxera were 

 found mostly in the spring, one should admit that they repre- 

 sent a series of alate virginoparse in the process of reduction, 

 but having been recovered only in the time and place in which 

 the pupse of alate sexuparse exist, one would be led to believe 

 that they are allied to them. She believes that, for unknown 

 reasons, the Phylloxera is able to change its destiny in different 

 stages of its development and that if it should change it in the 

 first or second stage it would still produce a normal individual, 

 while if it determines itself in the fourth it will probably become 

 an intermediate. The intermediate virginoparse, therefore, would 

 be considered as individuals, which, as far as the third stage were 

 going to become apterous adults. At this point, however, there 

 would come some change, which, while having an influence on 

 the character of the individual, would not be able to modify 

 the nature of the eggs, since this would probably have been 

 already fixed. The intermediate sexuparse would be, instead, 

 individuals which were to become alate, which had changed their 

 orientation in the third stage, when the nature of the eggs was 

 already determined. 



Dr. Foa appears to be the only worker who has recorded obser- 

 vations on the younger stages of these intermediates. She says 

 that the last nymphal stage of this form, more or less resembles 

 a pupa. She observed the moulting of tAvo individuals. One 

 of these, when adult, had wing rudiments slightly larger than 

 the pupal pads, while in the second they were smaller. 



During the past summer, in the course of a study of the life 

 history of the green apple aphis (Aphis pomi, DeGeer),at Vienna, 

 Virginia, we made numerous observations on an intermediate 

 form. The insects were reared on small seedling apple trees, 

 in pots, each plant being covered by a lantern globe cage. Alate 

 forms were of very frequent occurrence during the summer and, 



