420 INSECT FBEVENTION. LApRir., 



insect pests that were on or near the surface, that the plan might be 

 worth thinking of. The loss caused by this insect is a very serious 

 matter in Britain, a loss which the estimates made here show us 

 sometimes to amount to a sack per acre on seventy acres ; some- 

 times and more frequently in the years noted, to a loss of about 

 three sacks per acre. I have wished to draw attention to how, 

 in the very different methods of life of different insects, there 

 is often some one point of likeness in their habits, by which we may 

 check their over- increase. In the various methods of life we are 

 now considering, that point is winter shelter, and more particularly 

 shelter sought at the roots, or down or amongst the stems of grass or 

 stubble of various kinds. But there is yet one more of our bad farm 

 pests which I wish to say a few words about, as it differs from all 

 those that we have mentioned in its winter shelter, not being amongst 

 the perishing remains of the harvested crop, but in the heart of the 

 diseased growth which its presence causes in the winter corn or 

 kindred grasses. This is the attack most commonly seen on barley, 

 often known as 'gout,' from the swollen appearance of the 

 sheathing leaves where the diseased ear has not been able to free 

 itself. It is caused by a small, very thick-made, black or yellow, 

 two-winged fly — known in Germany from its attack being on the 

 haulm, as the haulm-fly — scientifically, as the chlorops Ueniopus. 

 This liy lays its egg at or near the base of the forming ear, and the 

 maggot which hatches from this egg eats its way down to the first 

 knot, forming thus a furrow in the stem which greatly interferes with 

 its healthy growth. By this furrow you may know the attack of the 

 haulm-fly. Its regular English name is the ribbon-footed corn-fly, 

 but as without a magnifying glass its feet are hardly distinguishable, 

 the German name of ' haulm ' fly seems the best. The maggot usually 

 turns to a chrysalis in the sheathing leaves, and the fly may sometimes 

 be found in great numbers in stacks just after they have been built 

 up, I have found these flies thus in vast numbers inljarley in this 

 county. Here we have a Idnd of fly which comes out of the attacked 

 corn in autumn, when it is plain beyond all doubt that there is not a 

 coming-on crop in half or three-(|uarter grown state with the ear just 

 formed for it to go to lay its egg in. The question has sometimes 

 been. What became of it until laying time next year ? But we are 

 told from Continental observations that there is an intermediate 

 winter brood. It appears that the autumn-bred fly lays its eggs on 

 autumn-sown corn or on grass. The maggot pierces into the neck of 

 the plant, and there it winters. In spring the shoot which contains 

 the maggot grows in a thickened form and with wide leaves, and 

 within it the haulm-fly goes through its changes, and from the 

 (commonly) destroyed shoot it comes out to start its summer attack. 



