HEMIPTERA 71 



DD. Prothorax normal. Leaf-hoppers. Jassidce. 

 CC. Wings entirely membranous or lacking. 



D. Wingless or with only one pair of wings. Wing- 

 less forms scale-like and, except in the very early 

 stages, without power of motion. Scale insects. 

 Coccidce. 



DD. Wingless or with two pairs of wings. All stages 

 active. Plant-lice. Aphididce. 



