198 MAINE AGRICULTURAL EXPERIMENT STATION. 



All the descendants of the original aphid or "stem-mother" as 

 she is called, ordinarily remain in the same leaf and the curl 

 becomes swollen and crowded with the numerous family. As 

 each individual casts its skin several times in the process of its 

 growth and as the discharge of honey dew is abundant, the curl 

 after a time has a considerable amount of waste matter which 

 causes it to look untidy within. Conditions are kept remarkably 

 sanitary, however, by the aid of the waxy secretions of the 

 aphids, particles of which cover the honey dew so that it rolls 

 about in liquid pellets without drenching their bodies. These in- 

 sects are further protected by the white waxy secretions which 

 remain upon them rendering them impervious to moisture. 



The earlier members of the family, including the stem-mother, 

 are all wingless. Late in June, however, a generation matures 

 with wings. 



These winged individuals, or "spring migrants" as they are 

 called, resemble the wingless generations previously mentioned 

 in being all females, but they are smaller bodied and differ in 

 various structures. Instead of remaining within the leaf with 

 their wingless relatives these later forms take flight, seeking 

 fresh vegetation for the establishment of the summer colonies. 

 They are strong on the wing and fly to distances of at least 

 three-fourths of a mile if they do not find a suitable location 

 near at hand. When they desert the elm leaf which has fur- 

 nished sap for their development they are "instinctively" led to 

 an entirely different habitat, namely the Juneberry (Amelan- 

 chier) so common in Maine and variously known as Shad Bush, 

 Service Berry, and locally as Sugar Plum. 



When the migrant reaches one of these bushes it settles upon 

 a leaf and soon afterward creeps to the underside where it 

 remains quietly, ordinarily for the rest of its life. Before 

 many hours it begins to give birth to young and continues this 

 process for several days. The wee aphids, born on the under- 

 side of the Juneberry leaf, cling there for a little while without 

 feeding and then walk down the stem of the plant. Sometimes 

 a line of these can be seen trailing down "Indian file," little 

 pellucid yellow specks so small that the observer almost requires 

 a lens to detect them at all. The destination of these minute 

 young is the underground stems of the Juneberry,, where they 

 settle in groups at some tender spot. 



