44 OHIO EXPERIMENT STATION; BULLETIN 198. 



FXPLANATION OF PLATE IV. 



a San Jose scale, enlarged. 



Negative by Houser, 



b Scurfy scale. 



Negative by Houser. 



c Adult apple tree tent caterpillar, female. 



Negative by Houser^ 



d Injury to twelve year old apple tree by wooly aphis. 



Photo by Goodwin, 



e Wooly aphis on young- limb of an apple. 



Negative by Houser. 



