58 BRITISH FERNS 
stage, the winged perfect insect commences to flit about. Keeping 
this fact in mind it is obvious that we have about a month in which, 
if attacked properly, we can absolutely clear all the plants without 
a chance of reappearance, unless other infected plants be intro- 
duced. Our remedy, which we have found to be exceedingly 
efficacious, is to use the liquid form of the “Х L АП” insecticide, 
which is vaporized by means of a small spirit lamp and an in- 
expensive apparatus, and, if used about the end of April, entirely 
kills out the larvae which by that time will have all been hatched 
out. It is equally effective later on when the fly appears on the wing, 
but as some of these may be at that time in the short chrysaloid 
stage, and therefore dormant, these will escape the fumes and 
appear later on in sufficient numbers to re-establish the pest by 
fresh eggs, which they are not long in laying, thus rendering a second 
fumigation necessary. The same remedy is equally fatal to Green- 
fly, and should be applied directly that pest makes its appearance. 
The same remark applies to Thrips, of which the White-fly is 
really a species. When using it, all ventilators should be closed 
and everything done to prevent the intrusion of fresh air or escape 
of poisoned air during the operation. The comparative proportions 
of space to be fumigated are marked on the bottles in so many 
square feet, which are easily calculated by multiplying the width 
of the house by the length, and then by the height, the average 
height being taken of the sloping roof. When the lamp is lit, the 
house should be closed at once and not opened until the following 
morning, a calm evening being chosen. 
The Weevil is a far more insidious foe and one much more diffi- 
cult to deal with, since it is immune from all fumigatory remedies, 
and even defies to a large extent, and in its beetle form entirely, 
the other insecticides put on the market. This pest is far more 
drastic in its operations than those already mentioned, since 
starting with it in its grub form, a curved, fat white maggot, about 
half an inch long, it devours the very rootstocks and roots of the 
plants, in the soil of which the eggs have been laid the previous 
autumn, so that in the early spring we may find the Fern loose in 
the soil and probably entirely dead, or only to be resurrected by 
one of the processes we describe in our chapter on Propagation. 
The Beetle, an almost black insect, with an oval body, about a 
third of an inch long and with a long proboscis flanked by two 
antenne half-way down it at right angles, emerges from the soil 
towards the end of April, and climbing up the fronds, preferring 
the rising young ones, eats pieces out of the edges, and as these 
gaps grow larger with the fronds the result is terrible disfigurement. 
Hartstongues are especially to their taste, but by no means ex- 
clusively so. Having described the two forms in which this -pest 
appears and its different modes of attack, we may now consider 
the best means to frustrate its malignancy. The presence of the 

