HESSIAN FLY. 
39 
As the difficulties of the past year have shown that it is almost 
impossible to name these parasites from descriptions alone, I do not 
add any; but it may be of use to mention that these parasite-flies are 
so small that it is almost impossible to distinguish the limbs with the 
naked eye, and that they may be known from the Hessian Fly by this 
possessing only one pair of wings, whereas the parasites have two pairs, 
excepting in the few instances in which these are abortive. 
Observations of Attack not being found present on Oats. 
Somewhat previous to July 27th a note appeared in one of the 
Scottish journals to the effect that a field of Oats in Brechin district 
had been badly injured by Hessian Fly. As the Cecidomyia destructor 
has hitherto not been known to injure the Oat-plant, further information 
and specimens were requested, but nothing further, so far as I am 
aware, transpired on the subject. 
Later on, that is, on August 11th, I received information from Mr. 
Thomas Bunker, of Goole, as follows, and desire particularly to draw 
attention to it relatively to it showing non-presence of the pest on 
Oat-plants, even when the Oat-plants and infested Wheat-plants were 
growing close by each other. Mr. Bunker is acquainted with the 
appearance of the “flax-seeds,” and forwarded confirmatory specimens. 
He observed:—“I regret to state that further researches have shown 
the Hessian Fly to be firmly established in this neighbourhood. Mr. 
Biley, of Hessle, came here last Monday, and we spent a few hours 
visiting some of the fields infested. 
“ In one field crops of Wheat and Oats were growing side by side. 
We thought it a good opportunity for testing the statement that the 
does not attack Oats. I have since found many Wheat-stalks 
attacked within a foot or two of the Oats, but failed in finding it on 
the latter plant, though I spent an hour and a half in the search. 
The leaf or sheath of the Oat fits so loosely on the stem, compared 
with that of Wheat, that I think it does not give the necessary shelter 
and protection to the larvae. 
“Very little Barley is grown in this district, and I have therefore 
had no opportunity of examining it. A farmer told me yesterday that 
there was not a Wheat-crop on either of his farms (more than two 
miles apart) that was not infested. He farms 500 or 600 acres.” 
On August 22nd Mr. Bunker sent me the following further report, 
accompanied, as before, by specimens of the “flax-seeds”:—■ 
“ On the 15tli I again tested the non-presence of the Hessian Fly 
on Oats. I was at Balne, a small township nine miles from Goole. 
The crop consisted of Wheat and Oats mixed. I was able to find the 
chrysalis on the Wheat, but m no case on the Oats. I enclose two 
specimens.” 
