170 DISEASES OF THE COTTON PLANT. 
St. Helena. Soon after they were found on all the sea- 
coast, from New Orleans to North Carolina. On the 23d 
of the same month they had destroyed almost all the cot- 
ton leaves, but suddenly left the plant, though not for the 
purpose of webbing, as many of them were young. The 
cause of their sudden disappearance is stated to have been 
that they were too much exposed to the powerful effects 
of the sun, in consequence of the plants being nearly des- 
titute of foliage, and not protecting them from its direct 
rays. 
Colonel Benjamin F. Whitner, of Tallahassee, has also 
written an interesting article on the depredations of this 
caterpillar in that vicinity. "In 1835," says he, "the 
crops were entirely exempt from the ravages of the cater- 
pillar. In 1836 it appeared by the first of October, but 
did no harm. In 1837 no mention is made of it. These 
notes were made in Madison county, Florida." 
Colonel Whitner then moved to Leon county, in the 
same State, where, in 1838, the caterpillar appeared early 
in August. The second brood stripped the plants by the 
20th of September, and were so numerous that, after de- 
vouring the entire foliage, they barked the limbs and 
stalks, and ate out bolls nearly grown. In 1839 they 
were less numerous, and appeared late. In 1840 they 
came out from the 15th to the 20th of July, and, by the 
6th of September, the plants were stripped of their leaves 
and young bolls, so that the entire crop was less than half 
of the average of other years. In 1841 this caterpillar 
was seen in Madison county from the 15th to the 20th of 
August, and in Leon county between the 20th of August 
and the 1st of September. The loss was serious, com- 
prising probably one-fifth of the crop. In 1842 no dam- 
age was done. In 1843 they appeared near Tallahassee 
