404 THE AMERICAN FARMER. 



egg-shells on a single leaf. &quot;With development the color becomes more dingy, or pale yellow 

 ish, frequently with brownish borders or a green curve, due to the coiled embryo, which may 

 be seen through the transparent shell. The young worm or larva eats its way out through 

 an irregular hole on one side, usually during the morning, ere the dew is dissipated, and 

 from three to four days after oviposition. This is the average time elapsing between the 

 laying of the egg and the hatching of the worm therefrom in ordinary midsummer weather, 

 but the time varies with the temperature, and a much longer period is required in spring 

 and late autumn. 



All eggs perish that are unhatched when overtaken by frost, as is not infrequently the 

 case. The vacated and glistening shell is more readily noticed upon the green background 

 than the unhatched egg. 



Humidity seems to favor hatching. Aphides or plant-lice are quite often mistaken for 

 the eggs of this insect, while the &quot; Mealy bug &quot; (Dactylopius adontdum), a species of Aleurodes, 

 the eggs of the lady-birds (Coccinellidce), those of the lace- wings (Chrysopa), and even a 

 minute snail, not uncommon on the cotton plant, are likewise so mistaken. 



The Worm or Larva. This is familiar to every planter. Varying greatly in ground 

 color, it is characterized by the particular position of the black piliferous spots upon the 

 head and upon the body; by the white ring which surrounds each of the latter; by its pure 

 white subdorsal lines and by its elongate and slender form. It is semi-looper, the first pair 

 of prolegs being very much reduced in size and seldom used, and the second pair, though 

 longer, only about half as long as the succeeding pair. 



The worm molts five times during growth and changes appearance but little after the 

 first molt. Exceptionally only four molts are suffered. 



The newly -hatched worm measures 1.6 mm., is of a uniform pale dingy yellow, with 

 polished black, slightly elevated spots, each bearing a short pale hair. Before the skin is 

 shed, the color often becomes slightly greenish, and sometimes inclined to orange. After 

 the first molt the piliferous spots are more conspicuous, the hairs from them longer and 

 black, and the characteristic markings appear, though less distinctly than after the second; 

 but from this time on, the prevailing color is exceedingly variable, being either of various 

 shades of pale or pea-green, or more or less intensely black along the back. 



The normal number of larval molts is five. This is the number which I have observed 

 during the autumn months, while in the midsummer, when the development is more rapid, 

 I have on several occasions traced but four. The term of larval existence varies from 

 one to three weeks. There is a very general belief among planters that the first worms of 

 the season are pale and the later ones dark, and while light and dark worms may always be 

 found together in spring, summer, or fall, it is true that the green ones predominate earlier 

 in the season and the dark ones later. 



Immediately after molting, the body is pale and without marking, a rule with all 

 molting animals. After the earlier molts, the cast-off skin, which remains more or less fully 

 stretched, is sometimes eaten. Some of the peculiarities of the habits of the worm deserve 

 mention here because of their practical bearing. 



Until after the second molt, it always remains on the under side of the leaf, feeding upon 

 the parenchyma, and leaving untouched the coarser veins, stomata and upper skin or 

 epidermis. The leaves where they are thus feeding present a blotched appearance, the semi- 

 transparent epidermis becoming pale yellowish, and these blotches are, as a rule, at once 

 distinguishable from other somewhat similar ones made by a few other insects. 



After the worm begins to eat entirely through the leaf, which is usually before the 

 third molt, but sometimes later, it instinctively ascends toward the top of the plant and feeds 

 on the more tender foliage, &quot; ragging &quot; it, to use the expressive language of the planter. 



It can let itself down by a web from the moment of birth, but can also fling itself from 



