reported that it was difficult to find a single cabbage worm in the 

 field ; and Dr. Boardman, in August, informed me that they were 

 very much less abundant in Stark county than usual. This differ- 

 ence, so favorable to the horticulturist, was due apparently to the 

 continued prevalence of the destructive disease of the cabbage worm 

 first reported by me in September, 1883. 



Numerous examples of its extraordinary destructiveness occurred 

 in the course of our observations. Visiting a cabbage field near 

 Champaign late in August, the owner of which had reported a few 

 days previously that it was being destroyed by the cabbage worm, 

 we failed to find, on twenty minutes' search, a single living larva, 

 the leaves being, however, badly riddled, and the dried and black- 

 ened remnants of the dead cabbage worms giving unmistakable evi- 

 dence of their recent presence. 



Hoping to arrange experiments for the artificial propagation of 

 this disease at a distance, where it had not yet appeared, I wrote 

 to several of my entomological correspondents, inquiring whether it 

 was discernible in their vicinities. I'rom Dr. Lintner, State Ento- 

 mologist of New York, I learned that it had appeared in that State, 

 information to the same effect coming also from Mr. Goff, of the 

 New York Experiment Station. In a subsequent letter, the latter 

 gentleman contributed also the interesting information that Prof. 

 Arthur, the botanist of the Station, had experimented with reference 

 to the contagious character of the disease by feeding portions of the 

 bodies of larvae, recently dead, to still living and healthy worms, the 

 effect being the speedy sickness and death of those thus treated. 

 From William Saunders, Esq., of Ontario, Canada, I learned, Oct. 

 5, that there seemed to be no traces of the disease among the cab- 

 bage worms of his vicinity. Prof. Snow, of Topeka, Kansas, in- 

 formed me, likewise, that it certainly had not appeared in that 

 vicinity; and Mr. E. W. Doran, of Loudon, Tennessee, Assistant 

 Entomologist of that State, reported to me, as late as October 19, 

 that he was unable to detect any evidence of its occurrence there. 

 In Iowa, however, I learned indirectly that it had appeared in the 

 fields in the vicinity of Ames ; but whether as a consequence of the 

 gradual extension of the area occupied by it, or as a result of the 

 experiments instituted for its propagation there the previous year, 

 my informant was in doubt. 



As no precise description of this affection has been published, 

 as far as I am aware, I give herewith one soon to appear in an ar- 

 ticle on the Contagious Diseases of Insects, now in press in the 

 Bulletin of the State Laboratory of Natural History. 



In this insect jlnchcrie is distinguishable with great ease and cer- 

 tainty by conspicuous external symptoms, the color alone of affected 

 larvae being, in fact, entirely characteristic and unmistakable. The 

 natural color of a healthy cabbage worm is a light lively green, 

 sometimes slightly tinged with yellowish, but without any approach 

 to an ashy or milky hue. As the first symptom oi Jlaclicric, how- 

 ever, the larva commences to turn pale, this paleness increasing 

 more or less rapidly until the color is almost milky ^yhite, only 

 slightly tinged with greenish. This discoloration is uniform and 

 simple, no other tint usually appearing until after death. Then, 



