UNCLASSIFIED PESTS 359 



The S alt-Marsh Caterpillar 



Estigmene acrcca Drury 



Nearly a century ago, T. W. Harris made a careful study of 

 the life history and habits of this insect, which he named the 

 salt-marsh caterpillar because of its injuries to hay grown on 

 the salt marshes of the Massachusetts coast. This name has 

 been retained though somewhat misleading, as the caterpillars 

 are not confined to salt marshes but also feed on a great variety 

 of grasses and garden crops including cabbage, beans and peas. 

 The insect is distributed throughout Nt)rth America from 

 Hudson Bay to Central America. 



Hibernation takes place in the pupal stage and the moths 

 emerge in late May and June. The moth has an expanse of 

 If to 2^ inches. In the female the wings are white and marked 

 with numerous small black spots. In the male the hind wings 

 and under surface are yellow and spotted as in the female. 

 The abdomen above is orange with three rows of black spots ; 

 the tip is white. The yellow, nearly spherical eggs, about 4^^ 

 inch in diameter, are laid in patches about the middle of June, 

 a single female laying as many as 1200 eggs. The eggs hatch 

 in about a week and the young caterpillars feed at first in 

 colonies but soon scatter. They reach maturity in about 

 seven weeks, that is, about the middle of August. The cater- 

 pillar is then about If inches in length and covered with long 

 Hiouse- and fox-colored hairs arising from large tubercles, 

 twelve tubercles to a segment. The nearly mature caterpillars 

 are often seen wandering about in search of food or places in 

 which to pupate. The cocoons are hidden away in any sheltered 

 place and are largely composed of the caterpillar's hairs inter- 

 woven with silk and lined with a layer of silk. The pupal 

 period in the summer lasts from two to three weeks. In New 

 England there are two generations annually. 



