PACK.4RD.] THE NORTHERN ARMY- WORM. 703 



from Saint John, yesterday afternoon, in considerable strength. Notwithstanding the 

 efforts to destroy them, they were marching on the city last night with apparently un- 

 diminished numbers. To-day they are gone. Considerable damage was done to grass, 

 turnips, and other root-vegetables. The army-worm recently invaded Grassy Island 

 in Saint John River, from which an annual revenue was derived from the sale of grass. 

 This year only one-lifth of the usual amount will be realized. There has been no gen- 

 eral invasion of this province, and the alarm has subsided. — (Boston Journal.) 



I have represented on the map showing the distribution of the north- 

 ern army-worra, its probable range. Having received the moth from 

 Texas, I think there is no reasonable doubt but that it also inhabits the 

 other Gulf States as far as and including Northern and Middle Florida. 



The army-worm appears in the wheat-fields when the " wheat is in the 

 milk." Previous to this the young larvae are not noticed. " When less 

 than half an inch long, the worms are scarcely recognizable as army- 

 worms," the general color being green and only feeding by night. Riley 

 states that "in ordinary seasons they are reported along the thirty-third 

 parallel, as in Texas, early in March, and about a week later with each de- 

 gree of latitude as we advance northward. Then, in Southern Missouri 

 they commence to march about the middle of May ; in Central Missouri 

 the first of June, and in the extreme northern part of the State about 

 the middle of the month. In the more northern New England States 

 they seldom do much damage before the middle of July (we should 

 rather say first of August). There may, therefore, be a difference of 

 over two months between the appearance of the worms in Southern 

 Missouri or Kentucky and in Maine." — (tiiley's Eighth Eeport.) 



The pupa. — The middle of August, the larva, full-fed, descends into 

 the earth a few inches, and there, by constant wriggling of its body 

 and the excretion of a sticky fluid, constructs a rough earthen cocoon ; 

 or often it merely constructs a rude cell of dry grass just below the sur- 

 face, and there in a day or two, probably, as is the case with most 

 moths, the mahogany-colored pupa, nearly an inch long, with wing- 

 covers reaching to the last third of the body, with two spines slightly 

 curved in, situated on the last segment, emerges from the outer larva- 

 skin or mask, and lying there ten or fifteen days, till the tissues of the 

 future moth shall be formed and hardened, discloses the imago or moth 

 the last of August. 



Dr. Fitch shows that the natural habitat of the army- worm is in grass, 

 in low lands. Mr. Eiley substantiates Dr. Fitch's opinion, and thus 

 accounts for the occasional undue increase of the caterpillar: "During 

 an excessively dry summer these swampy places dry out, and the insect, 

 having a wider range where the conditions for its successful develop- 

 ment are favorable, becomes greatly multiplied. The eggs are conse- 

 quently deposited over a greater area of territory, and if the succeeding 

 year proves wet and favorable to the growth of the worms, we shall 

 have the abnormal conditions of their appearing on our higher and drier 

 lands, and of their marching from one field to another." * * * "Thus 

 the fact becomes at once significant and explicable, that almost all 

 great army- worm years have been unusually wet, with the preceding 

 year unusually dry, as Dr. Fitch has proved by record." — (Kiley's Sec- 

 ond Report.) 



In this, as probably in all other insects, the unusual prevalence of the 

 individuals is due to unusually favorable conditions for the preservation 

 of the egg and the development of the caterpillar and chrysalis. It 

 should be borne in mind that in ordinary years, of the one hundred 

 eggs laid by each moth (if that be the approximate number), but a 

 small proportion hatch, being eaten by birds and possibly destroyed by 

 egg-parasites and by cold and damp weather. Should fifty or seventy- 



