ZOOLOGY. 353 



the years 1804, 1825, and 1846, during the last half century. These 

 facts are inexplicable unless referable to some peculiar conditions of 

 their economy in their native land. Little is known from what south- 

 ern direction they come, for like all insects of this family, their move- 

 ments are made at night, and the seaboard planter often rises in the 

 morning finding whole sections of his plantations covered with the 

 adult insects, busily engaged in depositing th^ir eggs on the tender 

 leaves of the cotton. There is, however, no regularity in the exact 

 month of their coming, for Mr. Chisolm says that on his plantations 

 they came in 1840, quite early, but in 1843, much later, and re- 

 mained until frost ; in 1846, in June ; and in 1849 and 1852, in 

 August. 



The cotton caterpillar is nearly always accompanied directly by 

 another insect called the boll worm, (probably one of the Noctuidce,} 

 which confines its attacks to the immature lint and seeds of the 

 green pods of the short-stapled variety of cotton ; and, as short cotton 

 is mostly cultivated in sections farther south than those of the long- 

 stapled variety, this boll worm is generally seen in Texas and Mis- 

 sissippi six weeks or so before the cotton caterpillar proper appears 

 on the coast of Georgia and Scuth Carolina. Little is known of its 

 habits more than this, for its ravages are comparatively so inconsider- 

 able, .that it attracts scarce any attention of the planter. Its concom- 

 itancy with the true cotton worm, however, is not a little remarkable, 

 and there is no doubt that it belongs to a different family of insects. 



The cotton insect having made its appearance, shows considerable 

 sagacity in always seeking first the most luxuriant fields. The eggs, 

 which are of a dull white color, are deposited singly, or at most, in 

 twos, on the under surface of the most tender leaves. Their period 

 of incubation is quite short, being six or seven days, and the time of 

 hatching is alw r ays after sunset or in the night. They then begin to feed 

 ravenously, growing in proportion ; their attacks being always confined 

 to the long-stapled variety when accessible, though when hard pushed 

 they will eat the short variety ; but never will they eat any thing else, 

 and if their numbers are disproportionate in excess to the cotton at 

 hand, they will die of starvation rather than touch any other vegeta- 

 ble. During their caterpillar state, they are almost wholly unaffected 

 by all changes in the weather, excepting cold ; for the heaviest rains, 

 and the severest gales of wind do not stay their movements, or pre- 

 vent in the least their devastations. Mr. Chisolm says that a very vi- 

 olent hurricane of two or three hours' duration which swept over his 

 plantations in August last, made no impression whatever on their pro- 

 gress. If, however, there occurs even a slight frost, they are killed 

 throughout. 



These circumstances are worthy of mention, as bearing upon the 

 probability of their tropical origin. Their larval state is of about ten 

 days duration, and during this time they moult two or three times, 

 changing their colors and general appearance in the same singular 

 manner as the canker worm of the North. The caterpillars, when 

 full grown and well fed, are 16-legged, of the size of a common 



