THE INSECT ENEMIES OF CEREALS BELONGING 
TO THE GENUS CECIDOMYIA. 
BY 
Henry Tryon. 
(Read on 5th April, 1894). 
The Hessian fly (Diplosis destructor), its nature and mode of 
injury, and the history of its occurrence and extent of its ravages 
on the Continent of Euroile, in the United States, in Great 
Britain, and in New Zealand, were first dealt with ; and then 
the wheat midges (Diplosis tritici and D. aurantiaca) and other 
destructive species were similarly treated of. 
These insects might, it was said, be regarded as forming 
two groups, the first containing the Hessian fly — the tiny mag- 
gots of which injured the stems of wheat in the regions of the 
joints ; and the second, including Diplosis tritici and its associate, 
which confined their attention to its florets, and consequently 
rendered them infertile. As a representative of the first of these 
divisions, Mr. Tryon exhibited a sample of the celebrated blue 
grass (Andropogon serieeus), regarded as being one of the best 
fodder-grasses in Australia, evei^ stalk of which had one or more 
enlongated swellings at the joints, and so was materially damaged. 
These galls had been occasioned by the grubs of a mmute gnat- 
like insect— Lasioptera vastatrix— specimens of which were 
passed around. This was the only cecidomyid which had hither- 
to been shown to be destructive to vegetation in Australia, Mr. 
P. A. A. Skiise, its describer, having reported that it was very 
injurious to fodder in the Parkes District of New South Wales, 
where alone it had been previously met with. This pest, it was 
remarked, is quite common in Brisbane and its vicinity, and 
doubtless does considerable harm. 
To explain the action of the wheat midge, Mr. Tryon 
further exllibited a second species of Diplosis which he had 
latelv found damaging the inflorescence of the broom soi^lu . 
