MONTHLY NOTES ON GRUBS AND OTHER CANE PESTS. 21 
to the cultural methods, for the owner supplies the required humus and 
ploughs at a season when the beetles are depositing their eggs—December 
to February. 
DESTRUCTION OF TACHINID PARASITES AT THE MULGRAVE. 
I regret that I am compelled to report that our colony of tachinid 
parasites of the beetle-borer was destroyed through the lack of co- 
operation on the part of the farmer on whose place the breeding cage 
was located. 
The understanding was that the borer-infested field was not to be 
cut until the end of the season, and that the part just around the cage 
was not to be burned. 
I was considerably disturbed to find, on 10th October, when I made 
a visit to the cage, after my return from the Herbert River, that the 
whole field had been burned and cut, and the cage had been dumped 
out and torn up in moving it into the adjoining field of young plant cane. 
Mr. Girault and I not only made two trips to Mossman to get this 
work started, but we have also had to make frequent journeys to this 
farm, so that the parasites would have every opportunity to become 
established. 
It is certainly discouraging to find that they now have no chance. 
The flies which we liberated, having reproduced, are dead, and the 
offspring are destroyed in the burning and the milling. It is only by 
a miracle that any of the flies could get away. 
I have not been able to see the farmer in charge of the place, for 
he was away from home; but the matter was reported to the management 
of the Mulgrave Central Mill, since they were so urgent that we co-operate 
in the matter of establishing these parasites in the district. 
THe LANTANA SEED-FLY. 
I was interested to note the remarkable distribution of the Lantana 
Seed-fly. It has apparently spread all up and down the coast, since its 
liberation in the Cairns district in February, 1917. I found them well 
established at Mossman, and even as far south as the Herbert River, 
where they were found all over the district. It is certainly remarkable 
that so small a fly could cross the natural barriers between the above 
districts, for there must be considerable stretches with no lantana for 
them to feed upon. 
These insects are doing excellent work wherever established. The 
eggs are laid in flowers, and the infestation is noticeable even on the 
green fruit, for it becomes discoloured with brown streaks, and usually 
withers and falls before becoming ripe. In practically every case the 
kernel of the seed is destroyed, so that it will not germinate, This, 
however, in no way affects the parent plants, which will live on for years 
