268 MAINE AGRICULTUKAl, EXPERIMENT STATION. ipij. 



Northern Curl of American Elm. 



Schizoneura ainericana in part, of authors. 



The popular name here applied to this species ma}' be unfor- 

 tunate as the same insect exists also in the south, but it is 

 apparently the most common aphid in the northern states inhab- 

 iting the roll or curl type of leaf deformation on Ulmus aineri- 

 cana. 



The stem mother matures in Maine early in June, in the 

 young roll. (Fig. 139A) At this time she is somewhat powdery 

 but if removed from the curl and examined in sunlight with a 

 lens her body is found to have a distinctly greenish cast. When 

 mounted alive on a slide in balsam there is no dark reddish stain 

 though the balsam may be slightly yellowed. This species may 

 be distinguished by these signs from the rosette dweller which 

 shows distinctly reddish in the sunlight and stains the balsam a 

 deep red when mounted alive. 



Figs. 132 and 133 show the antenna of this form which resem- 

 bles that of the rosette species closely. Indeed the antennal 

 joints of the first generation of both these species vary enough 

 in different individuals to make this structure of little value in 

 separating the curl and the rosette species in this stage. (32-13 

 and 32A-13). 



The second apterous generations however, are readily distin- 

 guished by their wax glands, those of this curl dweller being 

 arranged in an irregular rather elongate mass and not placed 

 about a clear central area as in the case of the rosette dweller. 



