1918-19.] Life-History and Bionomics of Myzus ribis, Linn. 87 
Fig. 3. — Curves showing the relations of the per- 
manent sen soria to the articulation of Joints 
V and VI. Sixty individuals in each curve. 
= Red blister form. 
= „ ,, First generation on 
green leaf. 
= Green leaf form. 
0 5 io 15 
Fig. 4. — ^Curves showing the relations of the 
permanent sensoria to the articulation of 
Joints V and VI. 
= Red blister form (60 individuals). 
= Their progeny transferred in first in- 
star to green leaves (38 individuals). 
The lower 
The abscissae represent the difference in — mm. between the sensorium and the articulation. 
t 100 
curves refer to the fifth, and the upper to the sixth, joint. 
