ILLUSTRATIONS. 9 



Page. 



Fig. 35. Aphidencyrtus aphidipJiagus: Adult 127 



36. Pachyneuron sp. : Adult 127 



37. Allotria sp. : Male, female antenna 128 



38. The convergent lady-beetle (Hippodamia convergens): Adult, larva, 



pupa 129 



39. The nine-spotted lady-beetle (Coccinella 9-notata): Adult 129 



40. The nine-spotted lady-beetle (Coccinella 9-notata): Full-grown larva. 129 



41. The spotted lady-beetle ( Megilla maculata): Adult, larva, pupa 1 . 130 



42. A South African lady-beetle, Adalia flavomaculata 130 



43. Syrphus americanus: Adult female and details of male 131 



44. Eupeodes volucris: Adult female and details of male 131 



45. Sphaerophoria cylindrical Adult female and details of male 132 



46. The golden-eyed lacewing fly (Chrysopa oculata) : Adult and details, 



eggs, larvae, cocoon 133 



47. Aphidoletes sp., a cecidomyiid fly enemy of the spring grain-aphis 134 



48. Aphidoletes sp., a cecidomyiid larva which attacks the spring grain- 



aphis 135 



DIAGRAMS. 



Diagram I. Maps of the United States east of the Rocky Mountains, showing 

 normal temperature and departure therefrom for the critical 



period December, 1881, to May, 1882 15 



II. Maps of the United States east of the Rocky Mountains, showing 

 normal temperature and departure therefrom for the critical 



period December, 1889, to May, 1890 21 



III. Maps of the United States east of the Rocky Mountains, showing 

 normal temperature and departure therefrom for the critical 



period December, 1900, to May, 1901 25 



IV. Maps of the United States east of the Rocky Mountains, showing 

 normal temperature and departure therefrom for the critical 



period December, 1902, to May, 1903 26 



V. Maps of the United States east of the Rocky Mountains, showing 

 normal temperature and departure therefrom for the critical 

 period December, 1906, to May, 1907 28 



