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XX. — The Progress of the Hessian Fly. By Charles White- 
head, F.L.S., F.G.S., of Banning House, Maidstone. 
The appearance and progress of the Hessian Fly in Great Britain 
in 1886 have been recorded in the report of Miss Ormerod, 
the Consulting Entomologist of the Society, and in the official 
report written by Mr. C. Whitehead, the Agricultural Adviser of 
the Privy Council, and reproduced in the last volume of the 
1 Journal. It may be instructive and interesting now to give an 
account of the spread of this insect during the present year, 
with some details of the injuries occasioned to corn crops by 
its action. 
In 1886 the attack of the Hessian Fly was first noticed at 
Revell's Hall, Hertford. It was confined to this farm and 
three farms near Ware in Hertfordshire, two farms close to 
Hitchin in Hertfordshire, one at Luton in Bedfordshire, and 
one near Romford in Essex. In Scotland the pupa-cases were 
only found near Inverness, and near CriefF in Perthshire. In 
1887 the insect was found in no less than twenty counties in 
England, and ten in Scotland, causing in some instances con- 
siderable injuries, as will be shown further on. 
During the last winter the pupa-cases were found in quan- 
tities by Mr. Palmer, of Revell's Hall, Hertford, among the 
cleanings or siftings, after threshing wheat grown in infested 
fields. From these, kept in breeding cages, specimens of the 
fly were bred in the late autumn, +hough no larvae were 
found upon growing wheat-plants in the autumn season. Nor 
were any larva3 discovered upon growing wheat-plants and 
barley-plants during the spring of 1887. Directly the wheat- 
plants and barley-plants began to ripen, the pupa-cases were 
seen in exactly the same circumstances as in the previous year, 
imbedded close to the second joint of the stem and covered by 
the sheathing leaves. As a rule there were two or three round 
a joint. In some cases four or five were present, and in a few 
instances even six or seven were seen near one joint. 
The injury caused to wheat-plants and barley-plants this year 
was exactly similar in its nature to that of last year ; in fact it 
was characteristic of the attack of this insect. It was very much 
more widespread, though perhaps not much more serious in its 
effects than at Revell's Hall in 1886, except in one or two 
places in Scotland, The stems of the plants both of wheat and 
barley were bent down at the second joints from the exhaustion 
of the sap of the plants by the larvae, as well as by their 
irritating action. The growth of the plants was checked, and 
either the formation of grains was altogether prevented, or they 
were rendered imperfect and small, and injured by the ears 
