94 Second Report on Economic Zoology. 



in contact with them, no harm is done. On the rest of the land I 

 should give a dressing of nitrate of soda at the rate of 2i cwt. to 

 the acre. 



" I am not quite certain as to the species attacking your land, until 

 I hatch out some of the flies, luit in two of our commonest kinds it 

 is noticed that the grubs come on to the surface at night, especially 

 on warm damp nights. When this takes place much benefit to grass 

 land has been derived ]jy rolling of a niglit. Of course this means 

 extra expense, but it has often am])ly repaid the extra cost of labour 

 in attacks on grass land. Certainly try rolling and bush-harrowing 

 when the flies appear and use nitrate of soda. 



" Although I'ape meal (or dust) keeps the grubs away from the 

 roots, it nevertheless does harm in the end, for it, undou])tedly, 

 attracts the insects wherever it is placed. 



" lUsulphide of carbon is highly inflammaljle and the fumes are 

 poisonous to num, so must be used with care." 



Corrosive sublimate was experimented with and wliere the land 

 was thoroughly soaked with a solution of 1 oz. in (J gallons of water, 

 many, but not all, of the leather-jackets were killed. As these larvae 

 feed on roots, not earth, we must not expect the same Ijeneflt to be 

 derived from its use as in earthworms. 



The worm-killer referred to by Professor Hall is made as 

 follows : — 



Mercury perchloride . . . .10 lbs. 



Hydrochloric Acid . . . . 4 lbs. 



Water . . . . . .6 lbs. 



To dilute for use, use ^ oz. fluid to three gallons of water 

 ( = 1 in 1000). For worms on lawns it is an excellent remedy. 



The secretaiy of the club wrote again in May and in this com- 

 munication stated as follows : — 



" We had thought of trying a small piece of ground with lime and 

 gas water. The ground where the damage was done is undulating 

 and we find that the higher parts have still some grass left whilst 

 the lower parts are bare." 



Lime, unless put on hot, would not do much good. 



These pests are always worse in damp low-lying parts of flelds, etc. 

 In some cases, damp areas which are, or rather were, always infested 

 have l)een freed from these pests by drainage alone. The flies seek 

 moist soil in preference, so fly to low-lying patches wliere the 

 moisture collects. 



