96 
MANGOLDS. 
the grubs feed on the leafage, but, failing this, go down and feed on 
the roots, gnawing them off about a quarter of an inch below the 
drill. Where this happens of course the plant dies, but where the 
leaves were only eaten back (it was observed by Mr. Sym Scott) most 
of the plants, although late, recovered. This point is very important 
practically, and attention was drawn to it some years ago by John 
Curtis, as a reason for not clearing off a damaged crop over hastily , for as 
soon as the grubs are full grown they stop eating, and if the plants 
have life in them they will at once make growth. Also (as noticed by 
Mr. Sym Scott) attack will suddenly cease on a crop simply from the 
time of change of the grubs to chrysalis state being come, and all the 
damage consequently being over. 
As the grubs go down into the ground to about three or four inches 
below the surface for the change to the chrysalis state, it would be a 
good means of preventing recurrence of the attack to disturb the 
surface, so as to throw these chrysalids out to be killed by exposure 
or by the birds. If all goes on naturally, and the grubs are left 
undisturbed, the Beetles would come up from the ground in about three 
weeks after the maggots went down. There appears not to be always a 
clear idea with regard to this insect as to whether it is a Beetle or a 
grub : this probably arises from its dark colour in grub as well as in 
beetle state, but a glance at the figures at the head of this paper will 
show the very different form. The grubs sent me mostly resembled the 
figure in outline at 4 ; they were as they reached me not so broad 
as 8, and were chiefly of a deep blackish tint. They have a pair of 
horny jaws, and three pairs of small legs. 
The Beetles are flattish, brown-black, slightly downy, and have 
three raised lines along each wing-case, and are to be found (as I 
mentioned in my Report for 1884, p. 61) during winter or early in the 
spring, sheltering under clods or stones, or in moss and rotten wood, 
and are common in April in dead animals. 
There does not appear to be any reason to suppose that this attack 
affects other field-crops than Beet or Mangold, although in one instance 
weeds appear to have been attacked in the infested field. Turnips and 
Carrots on the two sides of infested Mangolds escaped injury, and, 
judging from what has been recorded before, there would be no reason 
to fear danger to other crops put into infested ground, even when 
attack was known to be present, or immediately after attack. Besides 
Turnips and Carrots above mentioned, Parsnips, Potatoes, Peas, Beans 
and Cabbage have been recorded as all succeeding perfectly on land 
where the Mangolds had been destroyed. 
