302 



A A' ECONOMIC ENTOMOLOGY. 



the larvae first appear is apt to lessen subsequent injury, if it does 

 not prevent it entirely. The method of application now adopted 

 is exceedingly simple, consisting of a moderately stout, rather 

 elastic, pole, to the ends of which are attached sacks of a coarse 

 ducking material containing Paris green. This pole is carried 

 by a man on muleback, who rides between the rows, continually 

 jarring it so that the poison sifts through the sacks upon the 



plants. It has been found that undiluted Paris green used in 

 this way does not injure the foliage, while it is absolutely effective 

 as against the larvae. Sometimes the pole is made long enough 

 to hold four sacks, so that four rows are dusted at one time. This 

 is exceedingly simple and practical, and has the advantage of re- 

 quiring no expensive outfit. 



We have belonging to this series of semi-loopers a number of 

 moths belonging to the genus Plusia, and most of these have 

 somewhere in the middle of the fore-wing a dash, line, circlet, or 

 other marking of silver or gold. Sometimes the entire surface is 

 metalhc or golden, and the species, as a whole, are very hand- 

 some, with the ground color in most cases velvety gray or 

 brown. Bright colors or contrasting markings are rare. Several 

 of the larvae attack cultivated plants, but none as frequently as 

 that of P. brassiccs, the cabbage Plusia. The caterpillar is 

 green, with rather indistinct lateral lines, and is readily sepa- 

 rated from the butterfly larva of Pieris rapcE, because it lacks 

 one pair of abdominal legs and is not at all velvety in appear- 

 ance. Its fashion of humping itself" also separates it from the 

 other larva, which always rests fully extended. This may be 

 dealt with as has been already recommended for the other ' ' cab- 



FiG. 340. 



Aletia argillacea at rest and with wings expanded. 



