G4 CORN AND GRASS. 



mostly too dry to be injured at the time when the creatm*es 

 are developed in sufficient numbers to be mischievous." 



In an extremely bad outbreak of this Aphis on one hundred 

 and ten acres of Wheat, in Cheshire, during the wet summer 

 of 1879, the Wheat was March-sown, and was about six weeks 

 later than in average seasons ; and in the middle of Septem- 

 ber every green head in the field was blasted by them. — (S.L.) 



In another instance recorded the infested ears were noticed 

 as tapering from the middle upwards, and it was found the 

 upper half was mainly infested by the Aphides, this appar- 

 ently from being rather less advanced, and consequently 

 softer. 



The various observations point to any method of cultiva- 

 tion or date of sowing being desirable that will get the plant 

 on in good time, ahead of the main appearance of this kind 

 of Aphis. 



How this Aphis passes the winter in this country is not 

 clearly known, but it has been observed by Dr. C. Thomas, 

 late State Entomologist of Illinois, U.S.A., that when winter 

 Wheat appeared above ground in the autumn, the Aphides 

 appeared on it. He says : — " Here they work upon the leaves 

 and stalks singly while the weather is not too cold, but when 

 winter appears they move downwards towards the ground, 

 some of them at least entering the soil and feeding upon the 

 sap of the roots ; at any rate I find the apterous ones at this 

 time working upon the roots, but at the same time I find a 

 winged individual above ground. I have also observed them 

 heretofore at the root of the Wheat late in the winter, while 

 snow was on the ground, and what somewhat surprised me, 

 I found them busy at work under the snow, and the apterous 

 (wingless) females bearing well-formed larvae. I am therefore 

 led to believe that in this latitude the species passes the winter 

 in other than the egg state. This will also probably be found true 

 wherever winter Wheat is grown."* 



This Aphis has been recorded as infesting all our common 

 Corn crops, and many of the wild and cultivated Grasses. It 

 would appear, therefore, that such thorough cultivation of the 

 surface of the ground as would clear out any roots whether 

 of crop or weed Grasses in which the Aphides could shelter, 

 might be very serviceable, before putting in Wheat. 



The habit of sheltering in wild Grasses would quite account 

 also for the appearance of the insect in spring or early 

 summer on Corn growing near such shelters, and destroying 

 headlands and breadths of wild grass would do good. 



* ' Third Annual Eeport on Noxious and Beneficial Insects of the State 

 of Illinois,' by Dr. C. Thomas, pp. 53, 54. 



