614 Prof. Westw@@@ on the minute Diptera 
A note is added relative to MW. Frit and M. hordev, 
which Bjerkander regards as identical. 
The following communication, dated September 15th, 
1881, from J. ch Yonge, Esq., of Otterbourne, Win- 
chester, addressed to my self, introduces us to a minute 
species of Muscide, which, from the vast number of 
specimens observed, must evidently be very injurious to 
the crops of oats :— 
‘“‘Srr,—You may perhaps be interested in an unusual 
abundance of insect-life that has just occurred here. 
Mr. Dennis, one of the farmers, lately threshed about 
twenty-five quarters of oats in the field, and stored the 
grain in bulk in a loft. A few days afterwards a stratum 
of flies was seen on the top of the oats, coming up 
among them, and passing away through the windows. 
The stratum was about four feet long, one broad, and 
three inches thick, and being continually renewed from 
below asthose above passed off, an immense number must 
have gone through during the four days it was observed. 
T enclose a bottle containing a few {about 100] specimens. 
The grain does not appear to be injured. There are a 
quantity more of the same oats in a rick in the field 
where they were grown. Would you kindly tell me what 
is the species of fly, and what its habits, and the food of 
the larva? Whether it is one of those injurious to corn ? 
and if it would be prudent for the farmer to thresh out 
the rest of the oats as soon as he can for fear of damage 
by the maggots; or if there are any other precautions 
that would be prudent in order to destroy the eggs ?” 
_ In Kirby and Spence’s ‘Introduction to Entomology ’ 
(small edition, p. 95), the only insects which attack the 
oats are said to be the omnivorous wireworm (or larva of 
Elateride), and occasionally an Aphis; and Mr. Curtis, 
in his ‘Farm Insects,’ mentions Leucania obsoleta and 
Crioceris melanopa as feeding on the leaves of standing 
oats, and that the oat crops in Styria and Carinthia 
occasionally suffer from the attacks of the larva of a 
minute Tipula or Cecidomyia on the grains. Mr. Mark- 
wick also found a larva which he considers as that of 
the wheat midge in the husks of the wild bearded oat, 
Avena fatua (Linn. Trans., ill., p. 246). 
Many of the flies which accompanied Mr. Yonge’s 
communication to me were still alive. They are very 
