102 



li^JUKIOUS INSECTS 



soon perishes. Figure 68, shows at a, the Colorado- 

 beetle of the natural size, covered by this mite ( Uropoda 

 Americana, Eiley), the mite greatly magnified, with a 

 long filament wiiich helps it to attach itself to the beetle; 

 c, the penetrating organs; the claw at the end of these. 



SWEET-POTATO. 



The insects which attack the Sweet-potato plant are 

 few in species, and belong almost entirely to that group 

 of beetles popularly known as Tortoise-beetles. With the 

 exception of the Cucumber Flea-beetle (Haltica cu- 

 cumeris, Harr.), and a few solitary caterpillars, other 

 insects have not been found on this plant; still these 

 Tortoise-beetles are of themselves suflBciently numerous 

 in individuals and species to often entirely destroy whole 

 fields of this esculent, and they are especially severe on 

 the plants when newly transferred from the hot-bed. 



TORTOISE-BEETLES. 



{Cassidce.) 



These Tortoise-beetles have thus far been found in 

 considerable numbers in the Southern States, but the 

 cultivation of the Sweet-Potato is annually becoming 

 more general in northern localities, and as there is con- 

 siderable traffic in plants, it is probable that the insect 

 pests Avill spread as food for them is provided. Every 

 one who receives Sweet-Potato plants, or ^' sets," from 

 another locality, should carefully examine them before 

 they are planted, to see that no insect is introduced with 

 them. 



These insects are almost all of a broad sub- depressed 

 form, either oval or orbicular, with the thorax and wing- 



