DADDY LONGLEGS. 71 



time ; those on which the brine was merely poured were none 

 the worse." From these observations it appears that salt 

 cannot be trusted to as a means of killing the grub, and in 

 very wet weather when the rain washes it down quickly, it is 

 probably of little or no use ; but in moderately dry weather it 

 may be of some service in keeping the grubs from straying 

 about on the surface, as it annoys them. 



Nitrate of soda acts well, both by benefiting the plant and 

 injuring the grub. In experiment tried by myself I have 

 found immersion of the " grub " in a solution of the nitrate to 

 be followed by an immediate and violent discharge from the 

 intestines. 



Amongst the experiments tried by Mr. Lowe he placed 

 grubs in earth at a depth of within one inch of the surface, 

 and covered the surface above them respectively with an 

 amount of salt representing 1 ton per acre, lime 3 tons per 

 acre, and nitrate of soda 2 cwt. per acre. These were watered 

 with rain-water until the soil was well saturated, and "the 

 effect in salt and lime was not perceptible. The grubs treated 

 with the nitrate of soda were very relaxed, soft, and help- 

 less " ; and eight days after Mr. Lowe wrote that they still 

 continued limp and helpless. This helplessness is a very im- 

 portant point, for thus the grub, instead of creeping away, is 

 kept under the action of the solution good for the plant but 

 bad for itself, and ultimately dies. 



An application of 1 cwt. of nitrate of soda to Barley as soon 

 as well above ground had an entirely satisfactory result on 

 land where the previous crop had to be ploughed in conse- 

 quently on grub ravage. 



With regard to effect of cold, I was permitted to have some 

 specimens frozen by artificial means, at Kew Observatory, 

 down to a temperature of — 10°, that is, ten degrees below 

 zero, or forty-two degrees of frost ; and although most of the 

 grubs died, yet it showed that the grub could exceptionally 

 survive even this temperature, to all appearance quite un- 

 injured. 



The grubs have been noticed frozen until quite brittle, and 

 yet when thawed they were perfectly active. 



With regard to imiver of hearing immersion, I found by 

 experiment that although the grubs appeared to be dead after 

 remaining in water for about fifty-eight hours, yet that they 

 recovered after being exposed to the air ; the exact time at 

 which life was destroyed after being replaced in water was 

 difiicult to tell, but the whole time they lived from the begin- 

 ning of the experiment might be considered about four days 

 and nights ; it certainly did not exceed five days and nights — 

 that is, one hundred and twenty hours, for the grubs then burst. 



