206 D6 OHIO EXPERIMENT STATION: BULLETIN 194 



EXPLANATION OF PLATE IH. 



Fig'. 1. The pine leaf scale, natural size, with the twice-stabbed lady 

 bird, Chilocorus bivulnerus Muls. , feeding upon the scales. 



Fig. 2. Adplt females of the elnj bark louse. 



Fip ■'. The pine bark aphid upon the base of a pine. 



