BY HENRY TRYON. 
7 
will devastate the lucerne paddocks, but there is some reason to 
think that this will not be the case. It is more than probable 
that it is a native insect, although the attempt to detect its 
presence in indigenous Leguminosje has hitherto failed. How 
far it approaches in character the American Oscinis trifolii, 
also a small, rather robust, black fly, cannot at present be ascer- 
tained, since F. M. Webster, formerly of La Fayette, who first 
discovered it in 1886, has not yet published a sufficiently detailed 
description. 
The diet of the pest being restricted, it is recommended that 
whenever the presence of the latter is detected the entire grow- 
ing crop should be destroyed, and the ground occupied by it 
planted for a time with other vegetables. By this means it is 
hoped that the Oscinis may be locally stamped out. It is, 
however, interesting to record that at present it is preyed upon 
by two different kinds of minute hymenopterous insects. These 
are exhibited under the microscope, and there are also on view 
the living insect and its parasites, as well as drawings illustrating 
the ovipositor of the female fly, and the mouth -hook, and curious 
pedunculated spiracles of the maggot. 
[Mr. R. IiiLiDGE, during the discussion which this paper 
elicited, informed the meeting that he had met with the bean- 
maggot in his garden at Bulimba, and believed he had got rid 
of it by adopting a procedure similar to that recommended. — Ed.] 
CHALCEDONY. 
BY 
Henry G. Stokes, F.G.S. 
(Read on 5th May, 1892 : vide “ Queenslander,'' 14th May, 1892). 
