68 



injured the later sown plats, so that at harvest, July 5, these latter 

 were the poorest of all, the other three averaging about alike. All of 

 these plats during both years had been sown in narrow strips among 

 corn along one side, the remainder of the field being corn, and later 

 also sown to wheat, thus bringing the latest-sown plats between those 

 sown earliest and the entire field itself, as appeared to me, the severest 

 test to which I could subject the several plats. The results, while not 

 conclusive or even entirely satisfactory, indicate that in that latitude 

 about September 25 is, generally speaking, a good time to sow wheat 

 to escape fall attacks of the fly and winter killing. A series of plats 

 sown for me by Mr. Miles Martin, of Marshall, Parke County, Ind., in 

 very near the same latitude as Eichmond, but nearer the western border 

 of the State, gave rather more conclusive results, the sowings of Sep- 

 tember 22 being almost entirely exempt from the attack of the Hessian 

 fly, while earlier plats were infested. 



In regard to my own experiments here on the Experiment Station 

 grounds at Lafayette, 1 may state that I have never been able to pro- 

 voke a disastrous attack of the pest, though there has been nothing left 

 undone which could possibly induce the adult flies to oviposit at any 

 time between March and December; and there is probably not a month 

 between these dates during which the insect could not have been found 

 in all of its stages. The two destructive broods, however, invariably 

 appear in May and September ; in the latter case usually before the 

 20th. 



My own experimental showings were rather more elaborate and ex- 

 tensive than those of any of my correspondents, comprising a number 

 of varieties and extending over several months. Without going into 

 details, the experiments and results may be summarized as follows : 

 1887, plats comprising the varieties Michigan Amber, Clawson and 

 Velvet Chaff, each one width of a grain drill twenty rods in length, were 

 sown on the following dates: August 13, 27; September 10, 21; Octo- 

 ber 8, 27; November 5, 19. The autumn was very dry, and the plants 

 of the first six plats went into winter in poor condition, being very 

 small, while the last two sowings did not come up until the following 

 spring. The severe winter destroyed the plants so generally, that only 

 the first three produced sufficient grain to pay for harvesting. These 

 were also the only ones to suffer from the fall attack of the fly, the first 

 producing adults October 1. Plat 8 was attacked on the following June, 

 and on the 26th was badly infested with young larva?, full-grown larva? 

 and puparia, the latter, the most numerous, were found on the 16th of 

 July. The plats harvested produced a poor crop, but the Michigan 

 Amber ranked first, Velvet Chaff second, and Clawson the poorest of all. 



