SILVER Y-MOTH. 57 
insect seldom does any damage in this country. Of course abroad we 
know that Beet is very liable to severe attack.” 
On October 1st Prof. Foulkes, at my request, favoured me with a 
few more observations :— 
‘The field contained about fifteen acres of Mangolds, and was part 
of the home farm of Sir John Colomb, two or three miles out of 
Kenmare; the damage done by the pest would have been more 
apparent earlier in the season than when seen, viz. September 1st, as 
the August rains had no doubt saved the crop. Prof. Carrol and I 
estimated the damage then to mean a loss of about fifteen to twenty 
per cent. of the crop. If the crop had been in a dry district, I should 
very much doubt there being a crop at all. We found a few caterpillars 
still feeding, and I have wondered whether these could be a second 
brood. The pupz found were enclosed in strong net-work cases on 
the under side of leaves, and seemed capable of standing excessive 
moisture. I should be glad to know whether the pupa stage is ever 
passed below the surface of the soil; I ask this because we searched 
well the leaves, but only found a few pup, nothing like what we 
expected to find with so much damage. Neither was this due to the 
(shall I say) lateness, because we should in this case have found the 
remains of the cocoons upon the leaves.” 
Prof. Foulkes’ enquiry is one of very practical interest, but it does 
not appear that this moth does pupate under ground. The caterpillars 
by no means necessarily spin up on their food-plants; they are stated 
to form their cocoons on ‘‘ any plant,’’ and we had a good example of 
this in an observation sent me on October 8rd, 1888, by Mr. Geo. 
Brown, from Watten Mains, Caithness, N.B., where he had noticed 
caterpillars, which turned out to be those of the Plusia gamma, doing 
much harm to Turnip leafage. Amongst the specimens sent were 
some moth chrysalids in web cocoons, with the note: ‘Corn crops are 
perfectly covered with these cocoons; beneath the sheath-leaf and 
stalk in the corn, in the seed-stalks of Sorrel, and on every and all 
parts of the Field Thistle the cocoons appear”; and a little later on 
more specimens were sent, which showed the infestation to be of the 
P. gamma, the Silver Y-Moth. 
This moth is widely distributed, and often noticeable in summer 
and autumn flying about flowers in the day-time. The fore wings, 
which are upwards of an inch and a half in expanse, are of a satiny 
glance varied with brown and grey markings, and sometimes with a 
purplish or coppery lustre, and in the centre is the pale or silvery 
marking like the letter Y, from which the moth takes its name. The 
body is smoky colour, and so is the ground colour of the hinder wings, 
but these are sometimes of a whitish colour across the centre, ‘leaving 
a broad brown margin; the fringe is whitish, with a line of blackish 
