BY HENRY TRYON. 
83 
become established in Australia, this parasite will be available 
for a similar purpose to that subserved by the Senaiotellus nig- 
ripes, as above mentioned, in the case of the Hessian fly. The 
observations which led to the discovery of this broom sorghum 
cecidomyid were prompted, it was added, by our Agricultural 
Department, and to it, therefore, the Society was accordingly in- 
indebted. 
As a further instance of this class of insect pests Mr. Tryon 
exhibited a cecidomyid from Alternanthera versicolor a 
favourite plant for carpet work and borders of gardens. 
Abstract, 
PRESIDENTIAL ADDRESS, 1893. 
BY 
Henry Tryon. 
(Read on 10th April, 1894). 
[Tins address had for its subject “ A New Potato Disease,” 
and related to a malady, originated by bacteria, affecting this 
esculent in the Ravensbourne, Corinda, and other districts of 
Southern Queensland. The same theme formed the subject 
of a Special Report to the Department of Agriculture of Queens- 
land, and is alluded to in the Annual Report, 1893-4, of that 
institution. — Ed.] 
