I70 



THE AMERICAN ENTOMOLOGIST. 



liquid, it is necessary to frequently agitate 

 the mixture in order to prevent the poison 

 settling to the bottom, as well as to insure 

 its uniform distribution over the leaves. 

 But water is a heavy material to handle, 

 and unless one has the conveniences for 

 applying it, the dusting process will be 

 found the most economical, as requiring 

 the least labor. 



The recently introduced London purple, 

 referred to in our February number (page 

 41), may be applied in the same way as 

 Paris green, and will prove equally effec- 

 tive, besides being much cheaper. — A. S. F. 



THE NORTHERN ARMY WORM. 



There has been a very marked irruption 

 of this insect the present season in many 

 parts of Maryland, Delaware, and especially 

 in New York and on Long Island, where 

 the worms seem to be most injurious ; so 

 much so as to cause the leading daily jour- 

 nals of New York City to give a good deal 

 of attention to it. As is usual in such 

 cases a great deal of nonsense is published 

 and all sorts of explanations offered of 

 [Fig. 72.] ^'"'^ cause of their sud- 



den appearance. Since 

 our discovery and de- 

 scription of the eggs, 

 and of tlie method of 

 egg-laying as given in 

 the 8th and 9th Reports 

 on the Insects of Mis- 

 souri, and in the Walker 

 prize essay of the Bos- 

 ton Society of Natural 

 History for 1877, the 

 natural history of the 

 _ . ,,, insect may said to be 



Full-grown Ar.my Worm ■' ^ >^^ 



(after Riley). fully kuOWn. 



CHARACTERS. 



The worm when full grown is dingy 

 black in color, striped as in our illustration 

 (Fig. 72) with a broad dusky stripe along 

 the back, divided along the middle by a 

 more or less distinct and irregular pale 

 line and bordered beneath by a narrow 

 black line ; then a narrow white line ; then 

 a yellowish stripe ; then a narrow, indis- 



tinct white line ; then another dusky stripe ; 

 again a narrow white line ; then a yellow 

 stripe, and, finally, again a faint white line : 

 the underside or venter is obscure green. 

 [Fig. 73.] The chrysalis (Fig. 73) is 



mahogany-brown in color. 



The moth (Fig. 74) is of a 



Chr>sau. or armv ^^wn color, with a white 



Worm spcck near the centre of 



the front wings and a dusky, oblique line 



running inwardly from their tips. 



NATURAL HISTORY. 



The eggs are laid in the spring of the year 

 so far as we now know, and not in the Fall 

 as was formerly supposed. They are thrust, 

 by means of an ovipositor (Fig, 75, i^) admi- 

 rably adapted for the purpose, in between 

 the folded sides of a grass blade and glued 

 along the grooves with a white, glistening, 

 and adhesive fluid, which not only fastens 

 them together but draws the two sides of 

 the grass blade close around them so as to 

 pretty effectually hide them. The female 

 performs this operation at night and is ex- 



[Fig. 74.] 



Army Worm Moth :—a, male moth ; i, abdomen of fe- 

 male — nat. size ; c, eye ; e/, base of male antenna ; e, base of 

 female antenna — enlarged (after Riley). 



tremely active at the time, laying her eggs 

 with great rapidity, so that the ovaries are 

 soon emptied. Each individual egg (Fig. 

 75,^, A) is glistening white at first, but be- 

 comes dull yellowish toward maturity. The 

 female prefers a dry blade to a green one, 

 and is especially prone to oviposit in places 

 where there is a thick matting of coarse, 

 last year's grass. 



The young worm hatches in about ten 

 days, and up to the last molt has all the 

 habits of an ordinary Cut- Worm, the colors 

 being much paler than when full grown, 

 and the worm hiding during the day at the 

 base of the grasses. When not excessively 



