EXPLANATION OF PLATE XIX. 



CHIONASPIS SALICIS. (Page 180.) 



Fig. 1. Insects, natural size, in situ on willow branch. 



2. Puparium of adult female. X 1 5. 



2 a. Puparia with epidermal layer of bark on 



surface. X 15. 



3. Puparium of female at period of fecundation. 



X 40. 



3 a. The same, in profile, showing apterous male 



in act of copulation. X 25. 

 1. Adult female at gestation. X 45. 



5. Female at period of fecundation. X 70. 



6. Puparium of male, showing perfect insect 



casting off moulted pupal skin. X 35. 



7. Empty puparium of male. X 10. 



8. Apterous male. X 35. 



9. Winged male. X 35. 



