LIST OF ILLUSTRATIONS. 
Fig. 1. 
2 . 
3. 
4. 
5. 
6 . 
7. 
8 . 
9. 
10 . 
11 
12 . 
13. 
14. 
15. 
16. 
17. 
18: 
19. 
20 . 
21 . 
22 . 
23. 
24. 
25. 
26. 
27. 
28. 
29. 
30. 
31. 
32. 
33. 
34. 
35. 
36. 
37. 
38. 
39. 
40. 
41. 
42. 
43. 
44. 
45. 
49, 
47. 
Heteropterous insect. 
Psylla pyri .-. 
Wings of Siphonophora—illustrating the nomenclature 
Wing of Aphis mali. 
Wings of Schizoneura . 
Wings of Tetraneura. — 
Wings of Chermes . 
Apterous Plant-louse . 
Wings of Aphis mali. 
Wings of Schizoneura .. 
Siphonophora acerifoliae.. 
“ coreopsidis—Winged individual. 
“ “ Wingless individual . 
4 . 44 “ 
Wings of Aphis mali. 
Aphis mali—Wingless individual. 
(Erroneously numbered 14). 
Aphides.. 
No. 1. Aphis maidis—Winged insect. 
2. Head and antennae of Aphis mali. 
3. Aphis maidis—Winged female. 
4. Corn root infested by Aphis maidis. 
5. Glvphina ulmicola — vVings. 
6. Pemphigus poulicaulis—Wings. 
7. Head of Pemphigus. 
8. Wings of Phylloxera. 
Lachnus dentatus . 
Apple root Plant-louse. 
Root-louse Syrphus-fly . 
Glyphina ulmicola (Elm-leaf Cocks-comb—Gall Aphis). 
Elm leaf Cocks-comb gall. 
Omitted . 
Wings of Tetraneura ulmi. 
Pemphigus vagabundus. 
Poplar-leaf Gall-louse. 
Gall of Pemphigus vagabundus.. 
Gall of Pemphigus rhois.. 
Wings of Chermes laricis. 
Adelges of the Spruce . 
Tychea panici (omitted). 
Lady-bird larva. 
The Spotted Lady-bird. 
The Convergent Lafly-bird, Larva and Pupa. 
The 13-spotted Lady-bird.. . 
The 9-spotted Lady bird. 
The Trim Lady-bird.. 
The Twice-stabbed Lady-bird. 
The Twice-stabbed Lady-bird larva . 
Chrysopa-eggs, larva, cocoon and perfect insect. 
Syrphus fly . 
Larva of Syrphus-fly. 
“ “ feeding on a Plant-louse. 
Schizoneura americana. 
Pemphigus populi-monilis. 
Hormaphis spinosus. 
Pemphigus populi-transversus. 
Page. 
... 3 
... 19 
... 25 
.. 25 
... 25 
... 25 
... 25 
... 26 
.. 44 
... 44 
. 47 
... 59 
... 60 
... 60 
... 85 
... 85 
89 
116 
126 
131 
143 
143 
146 
146 
148 
152 
153 
155 
157 
173 
173 
173 
174 
174 
174 
174 
174 
177 
178 
179 
178 
202 
205 
207 
•208 
