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veloped in that field. These coming out among the yonng wheat 

 found immediate opportunity for oviposition, and, following the 

 usual habit of the species, proceeded to breed without delay. 

 Here at Edgewood, consequently, we had a practically isolated 

 experiment, not interfered with by invasion from without. At 

 Billett Station, however, the fly was common enough throughout 

 the country surrounding to do noticeable damage to fields not far 

 away, and there, doubtless, the repeated entrance of outside ima- 

 gos searching the country for growing wheat, lengthened out the 

 time of oviposition and the development of the brood. 



The isolation of the field at Edgewood gives us this further 

 valuable information. It will be remembered that the larvae col- 

 lected there September 22, first formed the puparia on' the 2d 

 October, and gave the first imagos on the 18th of that month. 

 Now, November 16, we found in this field an abundance of larvae 

 and puparia, most of the latter freshly formed, — necessarily de- 

 scended, therefore, from the imagos resulting from the first brood 

 of larvae developed in this plot. We have here, additional and 

 conclusive proof that the time required for the development of a 

 brood from the appearance of the puparia of one generation (Oc- 

 tober 2) to those of the next (November 16) is, at that season of 

 the year, about six weeks. 



To the above record of observations for the experimeutal plots 

 I need only add that a visit made November 23 to wheat fields 

 near Albion, Illinois, revealed the same state of affairs with re- 

 spect to the fly as occurred in these special cultures, about ten per 

 cent, of the examples found being puparia, and the remainder 

 naked larvae, mostly full-grown. Both these latest observations at 

 Edgewood and Albion were made during a period of severe frost 

 and falling snow; and they consequently show beyond question 

 the hibernation of the fly, in large part, as naked larvae. This 

 item in the history of the insect has been previously reported 

 only by Mr. John Marten, of Albion, whose observations were 

 printed in the "Fruit Growers' " Journal of Cobden, Illinois. I have 

 not seen the article, but Mr. Marten kindly furnished me, March 

 22, 1886, the following abstract of it, so far as it relates to this 

 subject: 



"Beginning in October, 1883, my observations extended to near 

 the middle of March 1884, during which time I examined several 

 hundred of the larvi^e. Many of them had not, up to the end of 

 February, formed the puparia, or outer hardened skins, in which 

 they usually pass the winter and undergo their final transforma- 

 tions. This, so far as I can learn, is a new feature in the habits 

 of the fly; and it is exceptionally strange at that time, as during 

 the period of observation we had a temperature of from 26° to 

 30' below zero, with intervals in which the fields were quite free 

 from snow. This change (the forming of puparia) began to take 

 place as early as October, 1883, but was not so marked in some 

 fields as in others. The unchanged Itivvixi were found in two 

 fields through January, 1884, and in one field which was well pro- 



