714 RosBert MATHESON 
The males are very few in number, comprising scarcely one per cent of 
the sexual generation. In many of the rearing cages, scarcely more than 
two or three males could be found among at least four to five hundred 
individuals. The few males present are always active, running about 
with great agility and mating with the females indiscriminately. Because 
of the very small number of males, undoubtedly hundreds and thousands 
of females are never fertilized. 
The oviparous female (Plate X XIII) 
Length 1.48-1.6 mm.; width 0.88 mm.; cornicles 0.32 mm. long. 
The oviparous females are wingless and are regularly oval in outline. 
They are variable in color, but are usually yellowish green tho dark green 
specimens are not uncommon and very frequently practically all the green 
Fig. 117. CORNICLES OF VARIOUS FORMS 
A, Aphis pomi, oviparous female; B, A. avenae, oviparous female; C, A. sorbi, oviparous female. All 
drawn to same scale 
