THE CABBAGE PLUSIA. 89 



narrow girdling band, had had the bark irregularly removed for the ex- 

 tent of an inch or more, as in Fig. 14. All of these later falling twigs 

 showed the interval that had elapsed between the injury and the fall, in 

 that the roughened edges of the bark left by the gnawing had healed 

 over with the peculiar roughened and rounded enlargement following 

 the deposit of the reparative material under such conditions. Some of 

 the twigs gathered gave excellent illustration of the ascent of the sap 

 through the outer wood, and its return, after assimilation in the leaves, 

 through the inner bark. In one instance, where the leaves were un- 

 usually large, the descending sap, arrested at the girdled point, had 

 built up structure in the tip until its diameter was more than double that 

 of the starved internode below, while the immediate point of the arrest 

 was quite enlarged from the material there deposited, as shown in Fig. 15. 



This peculiar attack did not extend to the other principal food-plants 

 of the Orgyia, as the horse-chestnut, maple, apple and plum, nor would 

 it be expected to occur in connection with growth and structure so dif- 

 erent from that of the elm. 



The same attack upon the elms, and to about the same extent, was 

 noticed by me in Troy, N. Y., six miles north of Albany. It has not 

 been reported elsewhere, although it probably extended to other locali- 

 ties where the Orgyia abounded under similar climatic conditions. It 

 was not observed in the city of New York, although the caterpillar was 

 very abundant there, and through its excessive ravages, attracted great 

 attention, as has been already referred to. 



Plusia brassicae Riley. 

 llie Cabbage Plimia. 



(Ord. Lepidoptera : Fam. Noctuid^e.) 



Kti.ky: 2d Kept. Ins. Mo., 1870, pp. 110-112, f. 81 (orig. descr. and notice); American 

 Eutomol., iii, 1880, p. 200 (cannibalistic habits); Ind.-Suppl. Mo. Repts., 

 1881, pp. 77-8 (descr.); in Papilio, i, 1881, p. 106 (differences from P. 

 id); id., ii, 1882, p. 43 ; in Rept. Commis. Agricul. for 1883, pp. 119-122, 

 pi. 1, figs. 2, 2a, pi. 11, f. 2 (habits, uat. hist., remedies, etc.). 



Thomas : 7th Rept. Ins. 111., 1878, p. 229 (habits and descr.); 9th Rept. do., 1880, 

 p. 40 ; 10th Rept. do., 1881 (figs, from Riley, brief descr. of larva). 



(iHOTE: in Bull. Buff. Soc. Nat. Sci., i, 1873, p. 147 (as P. ni) ; id., ii, 1875, p. 

 30 (catalogued as P. ni) ; in Canad. Entomol., vii, 1875, p. 205 (as P. 

 brassicw); in Papilio, i, 1881, p 127 (may be P. ni). 



Bethcne: in Rept. Ent. Soc. Ont. for 1871, p. 5, f. 93, 1872 (from Riley). 



Packakd : in Ilayden's 9th Rept. V. S. Geolog.-Geograph. Surv. Terr., 1871, p. 

 752, figs, a, b, c (from Riley). 

 12 



