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 makino- 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 Noctua 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 



