THE COTTON-WORM. 457 
of an inch long, destitute of legs, and unable to spin a 
thread. As these destructive wheat-caterpillars may be sep- 
arated from the wheat by threshing and winnowing, the 
chaff containing them may be put into large tubs, into which 
also a sufficient quantity of boiling-hot water may then be 
poured to kill all the insects. This will at least prevent 
their making their escape, completing their transformations, 
and laying the foundation of another brood. 
At the end of the tribe of owlet-moths may be arranged 
certain insects, which, from the structure of their caterpillars 
and their manner of creeping, evidently seem to connect 
this tribe with the Geometers. Some of these caterpillars 
have the first, and sometimes also the second, pair of prop- 
legs, under the middle of the body, so short, that they cannot 
be used in creeping ; others have only twelve or fourteen 
legs, the first pair of the prop-legs, or the second also, being 
entirely wanting in them. These caterpillars creep with a 
kind of halting gait, and arch up the middle of the body, 
more or less, with every step they take, thereby imitating 
the gait of the true geometers or span-worms. To this 
group belong the army-worms, or cotton-worms, which rav- 
age the cotton-fields of the Southern States. They have 
sixteen legs ; but the foremost prop-legs are shorter than the 
rest, and the caterpillars crook their backs in creeping, which 
has caused them to be mistaken for geometers by some 
writers. The cotton-worm is green, doubly striped with 
black on the back, and sprinkled with black dots. It grows 
to the length of an inch and a half, transforms in a kind 
of web or imperfect cocoon, and becomes an olive-brown 
moth, called Noctaa xylina by Mr. Say. It is found only 
as far as the cotton-plant is cultivated, and never occurs in 
New England. The twelve-legged caterpillars are sometimes 
injurious to cultivated vegetables ; but not enough so, in this 
country, to have attracted much notice. Their moths are 
distinguished by golden or silvery spots on their fore wings. 
The species, with the first and second pairs of prop-legs short 
58 
