ILLUSTRATIONS. 
PLATES. 
Page. 
Plate I. Fig. 1. — An old meadow near Ada, Minn., badly infested with leaf- 
hoppers. Fig. 2. — A brome-grass pasture on the Agricultural Col- 
lege Farm at Fargo, N. Dak., badly infested with leaf hoppers. ... 36 
II. Fig. 1. — Experimental plats on the Agricultural College Farm, 
Fargo, N. Dak. Fig. 2. — Experimental plats of the U. S. Depart- 
ment of Agriculture, at Arlington, Va. Fig. 3.- — A terraced farm 
in South Carolina, showing the uncultivated terrace strips in which 
the leafhoppers breed and from which they migrate to the culti- 
vated crop on the level 36 
III. Fig. 1. — Wild grassland in central Kansas, including grama grasses, 
buffalo grass, etc., infested by leafhoppers (DeltocepMlus, Athysa- 
nella, etc.). Fig. 2. — Wild grassland at Dickinson, N. Dak., with 
buffalo grass, grama grasses, and other native grasses, infested by 
leafhoppers (Deltocephalus, Athysanus, etc.). Fig. 3. — Small 
patch of cultivated irrigated grass in front of Mammoth Hot Springs 
Hotel, which was swarming with leafhoppers 44 
IV. Desert near Tucson. Ariz., containing small grasses occurring in scat- 
tered clumps among the desert vegetation, which are the home of 
various species of leafhoppers. Fig. 2.— Desert west of San An- 
tonio, Tex., containing plains grasses, swarming with leafhoppers. 
Fig. 3. — Desert land near Corpus Christi, Tex., containing grasses 
infested by leafhoppers 48 
TEXT FIGURES. 
Fig. 1. A leafhopper, Athysanus obtutus: Stages and structural details 52 
2. Drxculacephala reticulata: Adult and details, nymph 53 
3. Map showing distribution of Drxculacephala reticulata in the United 
States 55 
4. Drseculacephala mollipes: Adult and details, nymphs 56 
5. Helochara communis: Adult and details 61 
6. Hecalus lineatus: Male, female, nymph, details 64 
7. Dorycephalus platyrhynchus: Male, female, nymphs, eggs, details 60 
8. Parabolocratus viridis: Male, female, nymphs, eggs, details 68 
9. Platymetopius acutus: Adult and details 70 
10. Platymetopius frontalis: Adult and details 71 
11. Deltocephalus inimicus: Adult and details 73 
12. Deltocephalus inimicus: Nymphal stages 74 
13. Map showing distribution of Deltocephalus inimicus 75 
14. Deltocephalus nigrifrons: Adult and details 79 
15. Deltocephalus fuscinervosus: Adult and details 80 
16. Deltocephalus conjiguratus: Adult and details 81 
17. Map showing distribution of Deltocephalus affinis 82 
18. Deltocephalus affinis: Adult and details, nymph 83 
19. Map showing distribution of Deltocephalus sayi 85 
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