202 MAIXE AGRICULTURAL EXPERIMEXT STATIOX. I915. 



the accepted plant. Of course, since these plants were taKen from tne 

 open, there was every possibility that their roots might have been in- 

 fested also in the field. But fortunately one of the three plants was 

 kept moist under glass and upon this the progeny of the migrants col- 

 onized on the stem well above ground where there was no danger of 

 their being confused with field material. Some of the colony were still 

 alive 14 days later, but they did not thrive as did the underground 

 settlements. 



On Checkerberry Hill near Orono a solitary Juneberry not more than 

 eighteen inches high was found with several migrants on the underside 

 of its leaves. As this plant was about three-quarters of a mile froin 

 the nearest known elm, the record is interesting. 



June 28, near Orono, 415 of these migrants were counted resting on 

 the under surface of leaves of a single large Juneberry situated between 

 two large elms-. This number was onlj' a part of the migrants present 

 as those on the upper leaves could not be counted from the ground. 



During the week of June i"/, I spent parts of several days watching 

 some small Juneberries on the river bank ledges near Orono. The mi- 

 grants from elm were present and others alighted everj- now and then. 

 I saw their 3-oung trailing down the stem toward the ground, and found 

 colonies on the underground stems here as in the college woods. 



For the most part but one migrant occurred on a leaf, but where 

 leaf curls removed from elm were placed under caged Juneberries on 

 the ledge, as many as 16 migrants were found on the ventral surface 

 of a single leaf. Four other kinds of plants chanced to be under the 

 same cage and it was interesting to record that not a single migrant was 

 found on the under surface of the leaves of any of these. One was ob- 

 served walking restlessly across the top of a goldenrod leaf, but it did 

 not remain there. 



As will be seen from the date of the publication, this paper goes to 

 press before the fall migrants are coUected from Juneberry ; and the 

 statement in the life history account that the fall migration to the elm 

 is from Juneberry is based onh* upon what seems to be the inevitable se- 

 quel to the behavior of the spring migrants and their progeny on tne 

 Juneberry. Knowing the summer host and that migrants seek the elm in 

 the fall, the circumstantial evidence seems logically sufficient. 



The observation here recorded open up an interesting series of ques- 

 tions in regard to this wideh' distributed elm leaf species. Does this 

 insect occur on the elm only where that tree is within aphid flight ot 

 Amelanchier? If not, what summer host is accepted for sucn localities.-' 

 Are there circumstances where the elm, alone, is able to provide for ? 

 continuation of this species? Does it occur on the roots of trees of 

 shrubs botanicalh- related to the Juneberry and has it in such circum- 

 stances ever been confused with lan'igera? 



In connection with the last question it might be stated that the wax 

 gland areas of the summer root forms are different from those of 

 lanigera and would doubtless serve as a sufficient means of separating 



