150 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 3 



rendered still more urgent through the discovery- made by our vet- 

 erinary department that intravenous introduction into horses of 

 certain molds and bacteria found growing on the excrement of the 

 larva in many cases produces symptoms of blind staggers, and that 

 introduction per orem produces well marked cases. As the research 

 has gone forward the writer has become increasingly aware of the 

 magnitude of his task. He has come to see it as one requiring the 

 most fundamental sort of study for its completion. He has no thought 

 of attempting to offer at this time a complete solution for the problem, 

 but hopes merely to set forth briefly a method by means of which this 

 insect's injury to corn may be materially reduced. Only such facts 

 of the corn ear- worm's life history and habits as are necessary to the 

 development of methods of control will be considered in this paper. 



A majority of the third brood of larvge enter the soil and prepare 

 their winter burrows as has been described and illustrated by Quain- 

 tance and Brues.'^ The pupge into which they transform average 

 three and one-half inches below the surface with one and seven 

 inches as extremes. (This average was determined by the examination 

 of 503 pup^e collected from different cornfields about Manhattan 

 during the springs of 1908 and 1909.) Here they remain until June 

 of the following year. Having found the larvae feeding in great 

 abundance in weed patches and alfalfa fields in the early fall of 

 1908, the writer fully expected to take the pupae in such situations. 

 Although last spring a 10' x 10' area in a patch of velvet leaf, which in 

 the fall of 1908 was infested with many larva? of various sizes, and 

 several 5' x 5' areas in alfalfa, where in the fall of 1908 the moths 

 deposited their eggs thickly, were selected and carefully examined, 

 nothing could be found. It is probable that parasitic enemies and 

 sharp frosts destroyed the larva?. The data thus far accumulated 

 indicate that the corn ear-worm hibernates mainly in the soil of 

 infested cornfields. The number of pupae varies directly as the field 

 examined has been slightly or badly infested, and although more than 

 one half perish before emergence time from one cause or another, 

 enough survive as a rule to infest almost one hundred per cent of 

 the ears of the new crop without outside aid. 



The moths begin to emerge in late May and reach maximum emer- 

 gence in early June. Very soon after fertilization the females deposit 



' Dr. F. S. Schoenlebei- and assistants, chief of wliom may be mentioned Mr. 

 Thomas P. Haslam, of the veterinary department, Kansas State Agricultural 

 College, have recently found this to be the case. 



' 1905, Quaintance and Bi-ues, Bui. No. 50, Bu. of Ent., U. S. Dept. of Agric. 



