138 Second Report on Economic Zoology. 
I he best way to clear them out of the soil is to turn chickens on 
to the land when it is being dug in the spring ; they devour the 
larvae greedily. Neither soot nor lime have any effect on these 
insects. 
They may be killed in garden borders by injecting bisulphide of 
carbon into the ground. 
The adult flies appear in May and June; sometimes as early as 
the middle of April. 
The Mustard Beetle or Black Jack. 
( Phsedon betulse.) 
The beetles referred to by the correspondent from Downham 
Market under the name of “ Black Jack ” are the Mustard Beetle 
(. Phsedon betulse). 
An account of this pest will be found in the “ Journal of the 
Board of Agriculture/' vol. lx, no. 4, p. 524, 1903. 
The pest should be attacked by either collecting the beetles 
with tarred cloths or wooden scoops drawn between the rows as 
described on p. 525, or if a “ strawsoniser ” is available, by spraying 
with Paris green. 
All necessary information is given in the paper referred to. 
(Since this report was written the specimens of attacked plants 
have been received ; leaves and stalks were covered with Phsedon 
larvae of two kinds, P. cochlearise and P. betulse. These could only 
be destroyed by washing.) 
In answer to another communication, the correspondent was 
informed that the larvae of the Mustard Beetle which he forwarded 
would soon be mature ; they then enter the ground to pupate, and 
in fourteen days or so, the summer brood of beetles appears, and 
these beetles spread devastation over the advanced mustard crop. 
The larvae should have been previously attacked ; they are in all 
stages — some nearly mature, others only a week old. Unfortunately 
mustard is grown so close that more damage might be done by 
getting at the larvae than the latter do themselves, but with long- 
spraying rods large areas could be sprayed with a small amount of 
damage to the crop by the washers. 
Some plan should be adopted by growers so as to allow a free 
passage between the plants. 
