DISEASES OF THE COTTON PLAITT. 
Fuller, of Edisto island, South Carolina, te describes the 
depredations of the caterpillar in his neighborhood as 
follows : 
" In 1840, I discovered their ravages, confined to the 
luxuriant portions of the fields near the sea-coast of this 
island. The larvae were destroyed in the latter part of 
September. In 1843 they were first heard of by the 1st 
of September, when their ravages, limited as in 1840, 
were quite perceptible at some distance. A frost on the 
18th of that month probably destroyed them. In 1846 
they appeared on the 20th of July ; and by the 10th of 
September, I suppose there was scarcely a cotton leaf or 
any tender portion of the plants remaining, and the worms, 
not fully grown, deserted the ravaged fields by millions in 
search of food, failing to find which they died from starva- 
tion. The crop of this island was about forty per cent, of 
an average one. In 1849 the caterpillars made their first 
appearance on the 22d of August ; their ravages this year 
being confined to the low spots, caused no injury of 
moment. In 1852 they were found on the 10th of Au- 
gust about forty miles to the southward, and on this island 
about the 20th of the same month. They disappeared 
here, however, without doing injury. 
" Thus they have appeared at regular intervals of three 
years. In 1855, when they were again looked for, an in- 
tense drought from the early part of July was sufficient to 
prevent their increase, had they made their appearance. 
The old planters say that m 1804 and in 1825 they ap- 
peared as in 1846 ; that is, in periods of twenty-one years. 
" As near as I can judge, not having made any record, 
the length of time from the hatching of the egg to the 
chrysaUs is twelve days ; remaining four days in the chrys- 
ahs state, and six days more to the hatching of the egg. 
