FRIT-FLY. 
19 
Tlie following observations of Prof. M‘Cracken are well worth study 
relatively to date of sowing influencing amount of attack on the plant. 
The same coincidence of worst attack on the latest-sown Oats, and 
absence or slight presence of attack on the winter or early spring-sown 
Oats, has now been observed in two seasons, and the same coincidences 
have also been observed by Prof. McCracken in the case of the Gout- 
fly, or Chlorops tceniopa attack on Barley. This may reasonably be 
supposed to be because the plant got a good start, and if we could gain 
more observations on this point, particularly with some notes of 
weather accompanying, it might be a great help. 
Frit-fly, nat. size and magnified; and infested plant with maggot inside.* 
In 1888, Prof. M‘Cracken wrote me that a very large area in the 
district round Cirencester had suffered greatly from the Frit-fly attack ; 
the crop from which the specimens then enclosed were taken was 
practically destroyed, excepting for Hay; but he added, “ Winter Oats 
and all early spring-sown fields seem to have escaped.” 
In this past season (1889), Prof. M‘Cracken, writing from the 
Royal Agricultural College on August 1st, observed as follows:— 
“The Frit-fly has again been the most plentiful of injurious insects, 
and, as was the case last year, the degree of injury corresponds to the 
date of sowing. For example, in one field Black Tartarian Oats (the 
sort most largely grown here) were sown on March 29th, and enjoyed 
almost complete immunity from attack; in another field sown on 
April 29th, over seventy per cent, of the first stems were destroyed. 
The plants which had their first shoots killed in this way immediately 
commenced to tiller, so that the land continued to have a fairly close 
* Curtis’ figure of Oscinis frit is given to illustrate the paper, as even if there 
are minute differences between the 0. frit and 0. vastator, the above figure conveys 
an excellent idea of the Frit-fly which troubles us here. 
c 2 
