THE PALMER WORM. 439 



(5) The Palmer Worm — Chaetochilus pometellus : 

 Harris. There seems to be seasons when this 

 insect is very destructive. Generally they make 

 their appearance only in small numbers ; when in 

 quantity, their numbers are prodigious, and they 

 destroy all the foliage upon a tree in an almost in- 

 credibly short space of time. They prove most 

 injurious after a hot, dry season, when the orchards 

 which they attack appear as though fire had gone 

 over them. If an infested tree is shaken, hundreds 

 of them let themselves down to the ground by a 

 fine thread. Their attacks are not confined to the 

 leaves, but also extend to the fruit. They are very 

 variable in color ; and this circumstance has given 

 rise to their division into several species ; but spe- 

 cific diff"erence does not, probably, exist. Their 

 bodies have thirteen segments, and sixteen feet. 

 Their general color is greenish yellow ; but a shade 

 of pink, or a tendency to white, is often observed 

 among them. They have upon them several small 

 black dots, each giving rise to a single hair. Where 

 they exist in small number, they spin their cocoons 

 upon leaves ; but where they are numerous they so 

 completely destroy the foliage that this becomes 

 impossible, and they take refuge under dead leaves, 

 or some other material upon the surface of the 

 ground, or in any secure position. Their cocoon is 

 very superficial, when compared with that of some 

 other insects, as they remain in it a very short time. 



