374 The Spraying of Plants. 



It is a butterfly whose wings are "purplish brown above, with a 

 broad buff-yellow margin, near the inner edge of which there 

 is a row of pale blue spots. Expands from three to three and 

 a quarter inches." 1 The eggs are laid early in spring upon 

 willow, poplar, and elm trees, the young larvae appearing early 

 in June. When full grown the larvae are nearly two inches in 

 length ; the ground color is black, but it is relieved by spots 

 of white and red. During June the larvae pupate, the adult 

 appearing early in July. There are two broods each year, the 

 larvae of the second appearing in August. 



Treatment. The caterpillars are voracious feeders, and they 

 may be destroyed by arsenical poisons. 



1 Harris, "Insects of Mass. Injurious to Vegetation," 1841, 218. 



