PLUM APHIS OR " GREEN FLY." 147 



tcction." They are to be found collected in numerous colonies 

 on the under side of leaves of the young shoots, and are 

 sometimes found in parties on the stems of the green fruit. 



TliC winged viviparous * female (figure 1, p. 140) is one-fifth 

 of an inch in expanse of the fore wings, of which the mem- 

 brane is finely punctured, stigma greenish, veins brown. 

 General colour apple green ; head, horns, body between the 

 wings, knees, and feet black. Abdomen green, with four 

 lateral spots at each edge ; dorsum with a squarish spot and 

 two dark streaks below the cornicles (honey-tubes), which are 

 dark olive or only tipped with black. Legs yellowish. 



The tvingless viviparous female is of various tints from green 

 to olive brown, with three faint green stripes on the abdomen. 

 The horns short, olive brown ; the cornicles (honey-tubes) 

 very small, brown. TJie wltole body, above and below, jjowdered 

 with a cottony meal. 



The ivingless ovip)arons\ female "is greenish yellow, trans- 

 parent, usually shows the mature eggs within" (see figure 2, 

 p. 146). Of this it is noted that " the eggs in November are 

 ready for lajang, and freely pass from the body by a gentle 

 compression" (Gr. B. B.). 



The male is winged ; the body of a dingy ochreous colour, 

 with head, feet, honey-tubes, and various markings umber 

 brown; and some males wholly black. Has been "taken 

 rather numerously and in company with the oviparous 

 female on the Apple tree towards the middle of November" 

 <G. B. B.). 



The pupa (for form see figure 3, p. 146) is shining green 

 with shades of ochreous, two broad marks on the top of the 

 head; wing-cases tipped with dark brown; honey-tubes green 

 with black tips. 



One very important point in the life-history of this species 

 which distinguishes it from Pliorodon Jtumuli, the Hop Aphis 

 or "Plum and Hop" Aphis, which also infests the Plum, is 

 that this kind {Aphis j^i'nni) is not migratory. It does not 

 (like P. humuli) leave the Plum in early summer, and with the 

 autumn season return in developed form from the Hop to 

 hybernate. Observations in detail on this subject are given 

 from p. 153 onwards. 



Prevention and Piemedies. — Washes with a foundation of 

 soft-soap are the most desirable, because they have the great 

 advantage of sticking in some degree to the aphides. When 

 these insects (as before noted) are covered witli a kind of 

 mealy powder, many of the washes used simply run oil" them 



* Viviparous — producing living young, 

 t Oviparous — producing eggs. 



l2 



