PESTS OF TOBACCO. 255 



the eggs, flies rapidly from plant to plant, giving each 

 leaf upon which it deposits an egg, an audible tap. 

 This is done usually at twilight, and after, in clear 

 weather. The eggs gradually change their color to a 

 milky white, and even before the tiny worm breaks from 

 the shell, its spiral form is distinctly visible through 

 the transparent encasement. When first hatched, it is 

 of a delicate cream color, with a white, thornlike append- 

 age. When it has attained its full growth, which 

 occupies the period of about twenty days, it descends 

 into the ground, when its body contracts and shortens, 

 the skin meanwhile changing from a dark green to a 

 brown color and increasing in hardness; within a 

 week or two it will assume the chrysalis state, with 

 a long tongue case bent over circularly from the 

 head and touching the breast, making a complete loop 

 (Fig. 68), hence they are sometimes called "Jug handle 

 grubs." 



Entomologists usually concur in the belief that in 

 this condition it remains in the ground, below the 

 freezes, through the winter. Many practical, observant 

 farmers, however, are of the opinion that this is true 

 only as applied to those that appear later in the season, 

 just before, or after, the appearance of frost. It is be- 

 lieved that those coming to maturity in June and July 

 throw off the chrysalis state in August and September, 

 and appear as moths. In this way only can the large 

 number of worms that appear in these months be 

 accounted for. 



There is another moth, the Sphinx quinque-mac- 

 ulata, that resembles the latter so much that an ordi- 

 nary observer will scarcely distinguish the difference. 

 This is another species of the same family, and the 

 larvae of the moth prefer the tomato vine, especially in 

 the Southern States, but they are very destructive to the 

 tobacco plant in higher latitudes. 



