PLATE XIX. 



Fig. 1. — Chionaspis salicis-nigrcc Walsh, on Sali.v sp. Anal plate of fe- 

 male. 



Fig. 2. — Chionaspis a?nei-icana Johnson, on Uhnus ainerieana. Anal 

 plate of female, (o) Variation in margin of median and second lobe: (6) illus- 

 trates marginal variations and forked plates. 



