DISEASES OF THE COTTON PLANT. 167 
This caterpillar is farnislied with six pectoral, eight 
ventral, and two anal feet, of which, however, the two an- 
terior ventral ones are imperfect, small, and apparently use- 
less, so that its mode of progression somewhat resembles 
that of the span-worm, or looper, of the North, elsewhere 
described. 
In fifteen or twenty days after the caterpillar has at- ■ 
tained its full size it ceases to feed. It then doubles down 
the edge of a leaf, and fastens it with its own silk to the 
main part of the same leaf, or by webbing several leaves 
together, forming thereby a very loosely-spun cocoon. In 
this, it transforms into a chrysalis, which at first is green, 
but in a short time after changes to a chestnut-brown, or 
even to almost black. 
The first brood I raised were fifteen days in the chrys- 
alis state before making their appearance as perfect moths ; 
but, as this happened in a cold room and screened from 
the sun, I am of the opinion that, when they are exposed 
to a warm sun in the open fields, the time must necessarily 
be much shorter. I raised one caterpillar late in the fall, 
which was even thirty days before emerging from its 
cocoon ; but this I attributed entirely to the cold weather 
and non-exposure to the sun. This fact would tend to 
show that the hatching of the chrysalis may be delayed, 
by peculiar circumstances, until long after the natural 
time. 
The tail of the chrysalis is furnished with several small 
hooks, bent inward, by means of which it is enabled to 
hold fast to the loose web of which the cocoon is formed, 
while emerging from the chrysalis skin, or, in case of acci- 
dent, to prevent it from falling out of the cocoon during 
the prevalence of strong winds. 
There have been many speculations regarding the 
