LEPIDOPTERA. 251 



are increased or lessened at irregular periods, from causes which 

 are not well understood. These caterpillars are produced from 

 eggs, which are laid by the moths on the grass of the marshes 

 about the middle of June, and are hatched in seven or eight days 

 afterwards, and the number of eggs deposited by a single female 

 is, on an average, about eight hundred. The moths themselves 

 vary in color. In the males, the thorax and upper side of the 

 fore-wings are generally white, the latter spotted with black ; the 

 hind-wings and abdomen, except the tail, deep ochre-yellow, the 

 former with a few black spots near the hind margin, and the ab- 

 domen with a row of six black spots on the top of the back, two 

 rows on the sides, and one on the belly ; the under-side of all the 

 wings and the thighs are deep yellow. It expands from one inch 

 and seven eighths to two inches and a quarter. The female dif- 

 fers from the male either in having the hind-wings white, instead 

 of ochre-yellow, or in having all the wings ashen gray with the 

 usual black spots. It expands two inches and three eighths or 

 more. Sometimes, though rarely, male moths occur with the 

 fore-wings ash-colored or dusky. Professor Peck called this 

 moth pseuderminea, that is, false ermine, and this name was 

 adopted by me in my communication to the " Agricultural So- 

 ciety." Professor Peck's name, however, cannot be retained, 

 inasmuch as the insect had been previously named and described. 

 Drury, the first describer of the moth, called the male Caprotina, 

 and the female Acrea*, supposing them to be different species ; 

 but the latter name alone has been retained for this species by 

 most naturalists. 



In order to lessen the ravages of the salt-marsh caterpillars, and 

 to secure a fair crop of hay when these insects abound, the 

 marshes should be mowed early in July, at which time the cater- 

 pillars are small and feeble, and being unable to wander far, will 

 die before the crop is gathered in. In defence of early mowing, 

 it may be said that it is the only way by which the grass may be 

 saved in those meadows where the caterpillars have multiplied to 

 any extent ; and, if the practice is followed generally, and con- 

 tinued during several years in succession, it will do much towards 



* The proper orthography is Acr<Ka. 



