44 NEW YORK STATE MUSEUM 



Full-grown larva. Length one and one-half inches. Head dor- 

 sally, yellowish, obscurely mottled with dark brown, the genae light 

 brown, with irregular fuscous markings ; clypeus fuscous yellowish, 

 margined with a dull white which is produced posteriorly as a 

 median line ; labrum brownish transparent. Antennae light brown, 

 prothoracic shield mostly dark brown, variably mottled with fuscous 

 yellowish and with whitish median and sublateral lines. General 

 color of the dorsal surface of the body a light brown variably and 

 obscurely mottled with fuscous yellowish, the median and sub- 

 lateral dull whitish lines rather obscure, the tubercles large, dark 

 brown and the suranal plate mostly greenish yellow, the setae short, 

 stout, fuscous, the lateral stripe a variable dark brown mottled 

 obscurely with yellowish and reddish and margined ventrally with 

 a broad, irregular, dull whitish stripe with distinct reddish mott- 

 lings ; ventral surface mostly yellowish green, in some specimens 

 the greenish predominating, variably mottled with yellowish white; 

 truelegs mostly pale yellowish, apically reddish brown, prolegs pale 

 yellowish green. 



Another larva presents the same general appearance, differing 

 mostly in exhibiting indistinct, submedian, purplish stripes about 

 half the width of the lighter dorsal stripe described in the preceding 

 form. The lateral area is also somewhat darker and more distinct. 



Another light colored larva shows a distinct dominance of green 

 in the thoracic and anterior abdominal segments, the dorsal and 

 lateral lines hardly showing. 



Detailed technical descriptions of the egg and larva have been 

 given by Mr Chittenden in Bulletin 29, n.s., Division of Entomology, 

 United States Department of Agriculture, pages 16-18, 1901. 



Food plants. The original food plants of this species are with 

 little question various grasses. The caterpillars display a marked 

 preference for our small grains, such as wheat, rye, oats and millet, 

 and are frequently abundant in some other field crops, such as 

 alfalfa, clover etc., the injury to the different plants depending 

 somewhat upon their immediate availability ; that is, the outbreaks 

 by the fall army worm undoubtedly, as in the case of the true army 

 worm, begin with certain foci determined probably by the deposi- 

 tion of a considerable number of eggs upon preferred food plants. 

 It is inevitable, when the latter are devoured, that the larvae should 

 spread in the search of additional provender, and with such a gen- 

 eral feeder as this species, there is usually comparatively little diffi- 

 culty in securing something palatable and, as a consequence, severe 

 injury may be inflicted upon a considerable variety of plants. 



