144 Flies [CH. 
are. stamped out by means of a special instrument. 
Several thousands can be done in a day. They have 
a slit to the centre where it is cut as shown in Fig. 44. 
These are put round the stem 
of the cabbages at the time of 
transplanting. The cards must 
be put on carefully as their 
object is to prevent the fly 
from reaching the soil near the 
cabbage. They must be close 
to the ground otherwise the fly 
will crawl underneath. If the 
eggs are laid outside the card 
the larvae are unable to reach pea pa ble a ‘as 
the plants. The plants should eee is . ae ae 
be examined at the time of cabbage plants. 
transplanting and any infested 
with maggots should be burned. 
When transplanting a little soot and lime dibbled 
in with the plants helps to keep off the fly. 
In cases of attack infected plants should be pulled 
up and burned and the land dressed with gas lime 
after the crop has been taken. 
Cabbage and other cruciferous crops should not be 
planted the year following an attack, and all cruciferous 
weeds should be kept down. 
In gardens, sand containing paraffin (at the rate of 
% pint of paraffin to a bucket of sand) sprinkled round 
the plant will keep off the fly for a time, and may prove 
useful if done once a week until the plants have got 
a good start. 
The puparia remain in the soil or in the old stumps 
and it is important that means should be taken to 
