394: LET ID OP TEE A. 



the elm, and, according to Mr. Abbot, on the dogwood or 

 cornel, and the sassafras ; they feed well also on the leaves 

 of clover and Indian corn. They are of a pea-green color, 

 with a broad brown stripe edged below with white on each 

 side of the body, beginning on the fourth ring and ending 

 at the tail ; they are covered with spreading clusters of 

 green prickles, tipped with black, and of a uniform length ; 

 each of these clusters consists of about thirty prickles branch- 

 ing from a common centre, and there are six clusters on 

 each of the rings except the last two, on which there are 

 only five, and on the first four rings, on each of which there 

 is an additional cluster low down on each side ; the feet 

 are brown, and there is a triangular brown spot on the 

 under side of each ring, beginning with the fourth. The 

 prickles are exceedingly sharp, sting very severely when 

 the insect is handled, and produce the same kind of irrita- 

 tion as those of the nettle. When young these caterpillars 

 keep together in little swarms. They do not spin a common 

 web, but, when not eating, they creep under a leaf, where 

 they cluster side by side. In going from or returning to 

 their place of shelter they move in regular files, like the 

 processionary caterpillars (Lasiocampa jwocessionea) of Eu- 

 rope, a single caterpillar taking the lead, and followed closely 

 by perhaps one or two in single file, after which come two, 

 side by side, close upon the heels of these creep three more, 

 the next rank consists of four, and so on, the ranks contin- 

 ually widening behind, like a flock of wild geese on the 

 wing, but in perfectly regular order. When about half 

 grown they disperse, and each one shirks for himself. At 

 the age of eight weeks they get to their full size, in the 

 meanwhile moulting their skins four times, and finally meas- 

 ure two inches and a half or more in length. At this age 

 they leave off eating, crawl to the ground, and get under 

 leaves or rubbish, which they draw round their bodies to 

 form an outer covering, within which they make an irregular 

 and thin cocoon (Fig. 189), of very gummy brown silk, 



