500 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



serious pests of tobacco in the United States. They feed on the 

 green leaves, and, when abundant, may cause a loss of from 10 

 to 15 per cent, of the crop. Two species, somewhat similar 

 in appearance and habits, are found throughout the tobacco 

 growing regions. The northern tobacco-worm, Phlegethontins 

 quinquemaculata, is more common north of the latitude of 

 Washington, D. C.,and the southern tobacco-worm, P. sextata, 

 is the species usually destructive in the southern tobacco 

 fields . 



FIG. 236. Tobacco-worm, larva of the hawk-moth, Phlcgcthontius quin- 

 quemaculata, feeding on tomato. (About 1/2 natural size.) 



The adults, which are large grayish sphinx-moths, lay their 

 eggs on the lower surface of the leaves. The larvae feed on the 

 leaves and become full grown in about three weeks. They are 

 then three or four inches long and dark green in color with 

 white stripes on the sides. On the northern species these 

 white markings are V-shaped, while on the southern species 

 they are simply oblique lines. On the last segment of the 

 body is the conspicuous "horn," which has suggested the name 

 "horn-worm." The larvae burrow into the ground a few 

 inches before changing to the brownish pupae. In the pupal 

 stage the proboscis of the forming moth is inclosed in a peculiar 

 handle-like sheath. In some regions these pupae are known as 



