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INSECTS INJURIOUS TO COTTON PLANTS -g. 



, . One of the insects most 



destructive to the cotton 

 plant is the so-called boll- 

 worm, [Heliothis armi- 

 gera,) the caterpillar of 

 which, when young, de- 

 stroys the flower-buds and 

 young bolls, but when 

 older pierces the half or 

 full-grown boll, where it 

 devours the whole of the 

 interior part, consisting of 

 the unripe seeds and yet 

 unformed cotton, leaving 

 the outside of the boll uninjured, excepting where the worm has eflFected an en- 

 trance by gnawing a round hole, which is frequently stopped up by the digested 

 portions of the food of the enclosed caterpillar. 



The habits of this insect are as follows : The e^^ is generally deposited 

 singly on the outside of the involucel or outer calyx of the flower or young boll, 

 where it adheres by means of a gummy substance which surrounds the egg 

 when first laid, and which hardens by exposure to the atmosphere. It has 

 been repeatedly stated by planters that the ^^^ was deposited upon the stem, 

 and that the young stem forms the first food of the newly-hatched caterpillar; 

 but after a careful examination of several hundred stems, I found only one egg 

 placed in this situation, and that, from the fact of its being laid upon its side, 

 instead of the base, had evidently been misplaced. The (t^^ is deposited about 

 twilight, and is of a somewhat truncate, oval shape, rather flattened at the top 

 and bottom, and is grooved with projecting ridges on its side, which meet at 

 the top and bottom in one common centre ; its color is yellowish or pale straw 

 color until nearly hatched, when it becomes much darker, as the young cater- 

 pillar, which is inside, appears plainly through the translucent shell. These 

 eggs may readily be distinguished from the eggs of the cotton caterpillar or 

 cotton army-worm, for which they have frequently been mistaken, by their 

 oval, truncate form and yellow color, while those of the cotton army-worm are 

 very much flattened, and of a beautiful green color, scarcely to be distin- 

 guished from the leaf upon which they have been deposited. A single female 

 boll-worm moth, dissected by Dr. John Gamble, contained upwards of five 

 hundred eggs, so that it is no wonder they increase so rapidly. At the com- 

 mencement of the season only a few moths may be seen flying about in the 

 morning or evening twilight ; yet these seemingly harmless moths are the 

 parents of the second and third generations which spread such devastation 

 throughout the cotton fields. 



Some eggs of the boll-worm moth hatched in three or four days after being 

 brought in from the field, the enclosed worms gnawing a hole through the shell 

 of the egg and then escaping. They soon commenced feeding upon the tender 

 fleshy siibstance of the calyx, near the place where the egg had been depos- 

 ited. When they had gained strength, some of the boll-woi-ms pierced through 

 the calyx, and others through the petals of the closed flower-bud, or even 

 penetrated into the young and tender boll itself. The pistils ' and stamens 

 of the open flower are frequently found to be distorted and injured without any 

 apparent cause. This has been done by the young boll- worm ; when hidden 

 in the unopened bud, it has eaten one side only of the pistil and stamens, so that 

 when the flower is open the parts injured are distorted and maimed, and very 



