74 MAINE AGRICULTURAL EXPERIMENT STATION. I9I3. 



Alafe viviparous female, — Spring migrant. From late July 

 until mid-August this form can be found winged and solitary 

 in the gall which it is now ready to desert. Fig. 20 shows the 

 antenna of this form and Fig. 46 D. the wing. Fig. 21 is a 

 drawing of the antenna of the pupa, the joints IV and V of 

 which are typically rather short and bulging, and VI longer, 

 narrower and with nearly parallel margins. 



Apterous viviparous female, — Stem mother. This form has 

 not previously been recorded. I first took it in 1905 and have 

 met with it since though the galls of the progeny so far out- 

 number those of the stem mother that many occur to one con- 

 taining the apterous parent. Sometimes the stem mother is 

 present in one of a chain of galls containing pupae, but often 

 she is found in a single gall separate from those occurring in 

 a chain but not differing from them in structure or appear- 

 ance, — at least there is not enough difference so that those 

 containing the stem mother can readily be separated without 

 examining: the insect itself. 



Fig. 22. P. popidimonilis. Antenna of stem-mother. 



The antenna of this form (Fig. 22) is ordinarily 6-jointed 

 though sometimes, as is often the case with stem mothers of 

 allied species, there is some irregularity in the development of 

 the antenna and it appears with 5 joints. The joints have the 

 same rotundity as in the pupa, a character accentuated by the 

 shortness of IV and V which are literally about as broad as 

 they are long. 



Collection data for this species are as follows : 46-05. Popu- 

 lus balsamifera. Aug. 15, 1905. Veazie, Me. Several stem 

 mothers taken singly in galls but these were dead either from 



