14 



PAGE 



I aboratorj Experiments with Chinch-bugs 177-189 



The White Ant in Illinois 190-204 



Explanation of Plan- 205-206 



Appendix. The Mediterranean Flour-moth (Ephestia kitchniclla Zeller) 



in Europe and America 1-65 



rWENTIETH REPORT 



rntroductorj Note V 



I he San Jose Scale in Illinois 1-25 



Field Observations on the White-grubs 26-34 



Midsummer Measures against the Chinch-bug 35-44 



A Study of the Causes of the Disappearance of a Chinch-bug Outbreak.. 45-74 

 The Spontaneous Occurrence of White Muscardine among Chinch-bugs 



in 1895 75-78 



Miscellaneous Chinch-bug Experiments 79-102 



An Entomological ["rain Wrecker (Odynerus foraminatus SaussA 103-105 



Note on a New Disease of the Army worm 106-109 



Explanation of Plates 110-112 



Appendix. The White Pine Chermes (Chermes pinicorticis Fitch) I-XXV1 



TWENTY-FIRST REPORT 



Introductory Note IV 



Recent Work on the San Jose Scale 1-47 



The Economic Entomology of the Sugar-beet 49-175 



Examples of Insect Injury to the Beet 51 



Principal Preventive and Remedial Measures 52 



Classification of the Sugar-beet Insects 55—56 



Detailed Discussion oi Groups and Injuries 57-165 



The Red Spider (Tetranychus) 58 



The Beet Leaf-miners (Chortophila and Pegomyia) 59 



The Leaf-hoppers (Jassoidea and Delphacinee) 62 



The Treehoppers (Metnbracidee) 80 



Plant-lice (Aphididtc) 80 



The Flatas or Lantern-flies (Ormenis and Chlorochrga) S3 



The Pigweed Bug (Piesma cinerea) 85 



The Common Flower-bug t Triphleps insidiosus ) So 



The Leaf-bugs (Capsidce) 86 



The Smaller Plant bugs I Lygceidee) 93 



The Squash hug Familj I Corrida) 96 



The Stink-bug Family ( Pentatomidee) 97 



rhe Negro-bugs (Corimelanida) 99 



ctua } etc.) 100 



Leaf-rollers (Tortricidee and Pyraustidee) 105 



The Garden Web worms (Loxostege and Hellula) 106 



The 1 112 



Grasshoppers ( Acrididee and Locustidce) 128 



Other Leaf-eating Beetli and Silpha) 136 



Blister-beetles (Meloidee) 137 



Snout hynchophora) 142 



The Exposed Leaf-eating Caterpillars '. . 14? 



lice t - Iphididce and Coccidee) 159 



Win v, rteridce) 161 



White Grubs (Lachnosterna and Ligyms) 163 



Technical List of Sp< Insects 166-169 



Economic Bibliography 170-K S 



