gists, too, when searching for galls or Coleoptera, etc.,
often make good finds, and many interesting species
may be obtained through them. In short, express a
desire for specimens, and all the commoner species will
come to hand.
In all cases, or as far as practicable, the insects should
remain in situ on the food-plant, whether bark, leaf,
twig, or root. All superfluous parts, however, should
be cut away, and only such portion or portions re-
tained as may be needful. This if possible should be
done while the food-plant is fresh, and the leaves will
need to be fastened down with small card braces to
prevent them curling up. The insects often cover the
small branches of trees, and when such is the case they
may be removed with the bark, or the branch may be
divided longitudinally with a saw or split with a knife.
The ends of all the pieces of hard wood will need to be
pierced with a sharp penknife or very fine bradawl, so
that they may be easily pinned in the cabinet. Set
them aside to dry, away from the dust, and in a few
days they will be ready for the cabinet. The simplest
plan of finally mounting the specimens in the cabinet
46 COLLECTING AND PRESERVING COCCIM.
is the one universally adopted, and consists of merely
pinning the specimens in the cabinet in the ordinary
way with a reference number, and a record label at-
tached giving full particulars as to locality, date, ;m<l
name of food-plant, and collector's name. To me such
a system is anything but satisfactory; a collection tlius
arranged presents a very untidy appearance, and the
removal of specimens for microscopical study is only
too frequently attended with loss.
After many trials, the system which I have finally
adopted for the display of my specimens is as follows.
Lay in a stock of cork slips made from ordinary
cabinet cork ; size 3 in. X 1 in., which is the size of an
ordinary slip used for microscopical purposes. Care,
however, must be taken to have them of uniform size
throughout, or the result will be anything but pleasing.
The next process is to paper them. Take one of the
cork slips, and with ;i small <|iiantity of fish glue mi a
" dip stick," put a very narrow band of it all round
the edge of the slip. Having done this, lay the slip,
gummed side downwards, on the sheet of paper which
has been selected to cover it, and press it firmly all
round the edge. Do a number of slips in this way,
laying them side by side, leaving a space of halt an
inch between each of them. When the sheet of paper
has been filled with them, set them aside for a lew
minutes under light pressure, and afterwards separate
them with a sharp penknife; finally trim off the paper
from the edges of the cork slip with a pair of scissors.
You then have a cork microscopical slip ready for the
reception of the specimens at any time. When re-
quired for use attach a gummed microscopical label at
one or both ends, and in the available space left pin
or gum on the specimens. The best pins for the pur-
pose are those known as " Lills," which can be pur-
chased from any draper or silk mercer at 2s. 6d. per
dozen sheets. Gum, however, should only be used in
extreme cases. After fixing the specimens the pins
should be cut down to mere stumps, otherwise their
COLLECTING AND PRESERVING COCCID^. 47
numerous bright heads will appear more conspicuous
than the insects. In all cases the food-plant only should
be pinned ; and it is often necessary to use small braces
of thick black paper to hold leaves in position. The
labels will afford ample space for full data, etc. For
all species having white ovisacs or puparia black paper
should be used, and for dark species white paper.
Dull black " surface paper " and stout unglazed note-
paper are the best, and if the instructions given in
gumming be carried out the paper will not buckle. On
the other hand, if the whole surface of the cork slip be
gummed, the paper will buckle immediately, and
present an untidy appearance. When it is necessary
to show a larger series of any species than the limited
space on a single slip will contain, a second slip will be
required. This, however, need not be labelled, so that
the whole of the slip may be utilised ; care, however,
should be taken to have the reference number attached.
Having completed the mounting of the specimens,
all that is necessary is to fix them in their natural
order in the cabinet drawers, which can be readily
done with a pin at either end of the slip.
For my own part I prefer the slips mounted in
rectangular glass-topped boxes, as they present a much
neater appearance, and, what is more important, they
can be easily removed from the cabinet and examined
with a pocket lens without the least fear of damage to
the specimens. The advantages claimed for such an
arrangement are therefore obvious. The sizes of the
rectangular glass-topped boxes are 3^ inches by 2|
inches, and 5 inches by 3^ inches.
In order to bring the specimens as near the glass as
possible a strip of cork should be glued to the ends of
the boxes on the inside ; on these the slips, which can
be firmly attached with a pin at one or both ends, will
rest. By this arrangement the specimens are brought
nearer to the glass, and can be easily examined with a
lens without the removal of the lid. Duplicates may
be conveniently stored in shallow boxes or envelopes.
48 COLLECTING AND PRESERVING COCCIDjE.
As the external characters presented by the puparia
of many species are identical ; the student will find it
necessary at all times to examine microscopically the
minute structural characters of the insects. To enable
one to do this the insects must be treated with various
reagents and permanently mounted. The materials
required are
1. Ten per cent, solution of caustic potash (KOH).
2. Distilled water.
3. Absolute alcohol.
4. Stain ; for this I prefer " Crawshaw's magenta,"
which is sold in small packets.
5. Oil of cloves.
To prepare the Diaspinae scrape off a quantity of
the puparia (scales) into a sheet of white paper, and
either place the whole of this, or better still select
from the debris, the desiccated bodies of the insects;
place them in a small tube, fill it up with the caustic
potash, and plug with cotton wool. Place the tube
with the specimens inside a test-tube and half fill with
the caustic potash. Label the specimen (using a lead
pencil), and either set aside in a test-tube stand or at
once place it in a hot water bath. If necessary several
species may be treated at the same time. Larger in-
sects, such as Lecanium, Dach/lopius, etc., may be
placed in a test-tube. Boil the tube or tubes in a hot
water bath until the insects are* more or less trans-
parent, which takes from one to twenty minutes ac-
cording to the opacity of the insects, or rather the
solubility of the body fats. With the larger speci-
mens it is advisable to prick them with a needle
in order to liberate the fats, etc., and subsequently
shake them in a test-tube of water. In all cases
thoroughly wash in two lots of distilled water, and
afterwards
(a) Transfer to equal parts of alcohol and water ;
(/>) To absolute alcohol for a few seconds ;
(c) Stain with magenta stain dissolved in alcohol ;
(d) Wash in alcohol ;
COLLECTING AND PRESERVING COCCID^E. 49
(e) Soak in oil of cloves until all trace of air has
disappeared, and finally mount in Canada balsam in
xylol.
Should the oil not penetrate the specimens, gently
heat it, together with the specimens, over a spirit lamp.
The specimens will readily clear by this process, and it
entirely prevents fogged mounts.
Should air-bubbles occur in the specimen after mount-
ing in Canada balsam, place the mount over the gentle
heat of a spirit lamp. It is advisable, however, not to
apply heat except in extreme cases, as it destroys the
stain, and sometimes shrivels the delicate parts of the
insect.
The foregoing will serve equally well for all stages
of the insects; but for fresh examples of the males,
soaking in cold potash will sometimes give better re-
sults. Staining brings out the minute detail in a way
that nothing else can ; and I must here acknowledge
my indebtedness to my friend and co-worker Mr. E. E.
Green, of Ceylon, for the discovery of such an excellent
staining medium as Crawshaw's magenta; without its
aid it is well-nigh impossible to trace the minute but all-
important structural details. The density of the stain
may be regulated in the final washing of the alcohol.
There is yet another method of preparing the Coccidas
for museums, and this by making up life-history cases
of injurious, beneficial, and mimetic species. Of the
first we have at least four indigenous species in-
jurious to fruit crops, viz. Aspidiotus ostre&formis,
Curtis; Mytilaxpis pomorum, Bouche; Pulvinaria
ribesise, Signoret ; and Lecanium cori/li, Linn. And
there are only too many species injurious to our stove
and greenhouse plants which could be worked out in
the same way. The beneficial species of importance
are Coccus cacti, Linn. ; Tachardia (Carteria) lacca,
Kerr ; and Ericerus Pe-la, West. It may be well to
add that at the Liverpool Museum there are very
interesting life-history cases of the two former species
mounted together with personal ornaments, etc., made
4
50 COLLECTING AND PRESERVING COCCID^E.
from the natural products of these insects. Such ex-
hibits are highly educational, and so also are the life-
histories of the injurious species.
As to the mimetic species, I may mention the extra-
ordinary Physokermes abietix, Geoffrey. The female
of this species locates itself behind the old bud-scales
of the spruce fir, and so exactly resembles the un-
opened bud of the tree that it is difficult at first to
detect it.
Mould is the greatest enemy to the specimens,
especially to those having delicate waxen coverings or
ovisacs, which when once infested are utterly useless
as museum specimens, as they can never be restored.
The best preventive against mould is the free use of
carbolic acid in the cabinet drawers or boxes, as the
case may be. Mould is generally set up by an excess
of moisture. In my own collections this has been un-
doubtedly due to the gum used for mounting the speci-
mens, or from portions of the food-plant which had
not been thoroughly dried before placing them in the
cabinet. By adding a few drops of carbolic acid to
the gum, and by thoroughly drying the specimens,
mould may be prevented, providing always the speci-
mens are housed in a dry place. " Mites " (Psocidse)
simply revel among stored specimens of the Coccida?,
but the free use of naphthaline of the form known MS
albo-carbon is a perfect preventive.
METHODS OF PREVENTION AND REMEDIES.
As Coccids subsist upon the sap or juice of the plant
which they attack, by sucking it up with their rostrum
from the interior of the leaf or twig, it is obvious that
any application made for their destruction must neces-
sarily be such as will kill them by affecting the respi-
ratory organs, such as hydrocyanic gas ; or by direct
contact with their bodies, such as washes and emul-
sions. Paris green, or any such mineral poison which
METHODS OF PREVENTION AND REMEDIES. 51
has to be taken into the body before it becomes effec-
tive, is of no use against " scale " and " mealy bug," or
aphides, or any insect which lives by suction.
In this country there is no organised system of pre-
vention against the introduction of insect pests, which,
to say the least of it, is a very unsatisfactory state of
affairs, resulting only too frequently in the introduc-
tion of new Coccids from all quarters of the globe.
As instances of such introduction I may mention the
following species, which, with two exceptions, have
thoroughly established themselves in this country :
Aspidiotus alienus, Newstead. Discovered in 1889
by Mr. E. E. Green.
Diaspis (Aulacaspis) pentagona, Targ.-Tozz. Im-
ported from Japan in 1898.
Mytilaspis citricola, Packard. Common on imported
oranges and lemons, and quite recently on cultivated
plants.
Ischnaspis filiformis, Douglas. Discovered in 1887,
when Mr. Douglas first described it. It occurs now in
many places as a greenhouse pest.
Gymnaspis aechmece, Newstead. Quite a recent in-
troduction. It is now well established and increasing.
Fiorinia fioriniae, Targioni-Tozzetti. A pest on palms
in many districts.
F. Keivensis, Newstead. Quite recently discovered.
Pinnaspis pandani, Comstock. Chiefly a palm pest,
and very destructive.
Orthesia insignis, Douglas. Steadily increasing, and
extending into fresh districts.
leery a segyptiacum, Douglas. The plants upon which
this species was imported were all destroyed, and no
trace of the insects have since been found.
Thus within the last twelve years we have seen the
introduction of at least ten species of Coccids, of
which Orthesia insignis may prove as injurious to our
cultivated plants as our common " mealy bugs " (Dae-
tylopins, spp.), and it is much more difficult to destroy
than the latter. It needs, therefore, no further com-
52 METHODS OF PREVENTION AND REMEDIES.
ment of mine to show how important it is we should
take every precaution to guard ourselves against such
introductions, by careful investigation and treatment
of imported plants immediately on arrival in this
country. Seeing that we have no recognised system
of dealing with wholesale consignments of infested
plants, it may be well to consider how such work is
carried out in other countries. In his admirable work
on the Coccidae of Ceylon, Mr. E. E. Green enters
fully into the subject, describing the treatment as
adopted by himself, from information supplied by Mr.
C. P. Lounsbury, Official Entomologist at Cape Town.
As I do not possess Mr. Lounsbury 's official work, I
have taken the liberty of extracting from Mr. Green,
who says, "For wholesale Fumigation of plants and
fruits there is nothing to equal hydrocyanic acid gas,
generated by mixing cyanide of potassium, water, and
sulphuric acid in certain proportions. This treatment
is cheap and effectual. The gas is of the most deadly
nature, and will penetrate every crack and crevice, and
do its work thoroughly. 'The application is quite
simple. All that is required is a close-fitting chamber,
provided Avith a flue for the escape of the gas after the
operation. The more airtight the chamber the more
complete will be the work. It should be fitted with
racks to receive moveable trays, upon which fruit may
be spread. The objects to be fumigated are placed
into position ; the chemicals are mixed in a leaden or
earthenware pan and placed on the floor, the door shut,
and the room kept closed for from half to three quar-
ters of an hour. The flue is then opened, and after a
sufficient time (about half an hour) has been allowed
for ventilation the door is unlocked, and the plants, etc.,
removed. It is not advisable to take the subjected
plants directly into the open air if the sun is shining.
They should be kept for a few hours under shade,
which will greatly lessen any danger of damage.
" Mr. C. P. Lounsbury, Official Entomologist at Cape
Town, has kindly supplied me with full particulars of
METHODS OF PREVENTION AND REMEDIES. 53
the work of the fumigatorium at that place. From his
letters and reports I have extracted the following di-
rections and suggestions : ' For each 300 cubic feet
of space enclosed (and in proportion for greater and
smaller spaces) one ounce of 98 per cent, potassium
cyanide, one ounce of sulphuric acid, and two ounces of
water will be required to generate gas of sufficient
strength to kill the insects. Double this strength, or
the same amount of materials to 150 cubic feet en-
closed, may be used upon woody plants without danger
of seriously injuring them. The greater strength
should be employed whenever practicable, as it will
ensure the death of the eggs as well as the active
insects.'
" Imported plants are usually in a more or less dor-
mant condition, which lessens danger of injury. Mr.
Lounsbury writes, in his report of June, 1897, ' Injury
to the tips of new growth generally results. This in-
jury is in 110 wise serious, and is quickly outgrown.
The operators consider it a favourable indication, as
when such injury results it is quite certain that the gas
has been present in sufficient strength to destroy all of
the insects.'
" With respect to fruit, I again quote from Mr.
Lounsbury's letter : ' I had had lemons and oranges
analysed after treatment, and found that after a few
hours not more than a trace of the gas remained in the
rind. There is much more natural cyanogen in a
single seed (so the analyst told me) than what remains
in the fruit from fumigation. We have no complaints
of any effect on the keeping qualities of the fruit.'
" To generate the gas the required quantities of
cyanide and water are first placed in the generating
vessel, the cyanide being broken into small pieces
about the size of lump sugar. The operator then adds
the acid, pouring it slowly into the vessel to avoid
splashing, and immediately withdraws.
" The above treatment is suitable for fruit and hardy
plants. Tender garden plants are usually imported in
54 METHODS OF PREVENTION AND REMEDIES. '
Wardian cases, and may be treated separately. We
have in the ' Wardian case ' an airtight chamber
ready to hand, in which the plants can be fumigated
before their removal. After a large series of experi-
ments with various fumigating media, I find that
hydrocyanic acid gas remains by far the most efficient
insecticide, and the least injurious to the plants. But
with delicate succulent plants I find it has to be ap-
plied rather differently. A more concentrated dose of
the gas applied for a shorter period is most satisfactory
in its results. In a Wardian case containing about
sixteen cubic feet I find a dose of half an ounce cya-
nide, half an ounce acid, and one ounce water, with an
exposure of half an hour, will kill every individual of
a colony of Orthezia (the most resistent of all Coccids)
without in the least affecting the plants. ' The treat-
ment should be carried out only after sunset. Ac-
cording to Mr. Lounsbury's tables, these proportions
of chemicals should be sufficient for a space of 140
cubic feet with a longer exposure."
Mr. Green further describes the treatment of orchard
trees on a large scale, quoting again from Mr. Louns-
bury's method.
" Generation of the Gas. Hydrocyanic acid gas is
generated by the action of sulphuric acid on potassium
cyanide in the presence of water. The required quan-
tities of the cyanide and water are first placed in the
generating vessel, the cyanide being broken into small
pieces not above the size of lump sugar. The tree is
then covered with the tent or sheet, and the vessel
slipped under almost to the base of the tree. Reaching
in, the operator then adds the acid, pouring it slowly
into the vessel so as to avoid its splashing, and thus
burning his hand or the cloth. He immediately with-
draws, and the men shovel a little soil on the edges of
the cloth all around, to more thoroughly prevent the
escape of the gas.
" The rapidity of the evolution of the gas depends
largely upon the size of the pieces of cyanide. If
METHODS OF PEEVENTION AND REMEDIES. 55
these are like powder the reaction is violent and
immediate, but if in lumps the reaction takes place
more slowly, and continues for a minute or longer.
The slow reaction is desired partly because less
injury results to the foliage immediately above the
vessel. But the lumps must not be too large, for then
the reaction is liable to be imperfect, owing to a black
coating (carbon ?) forming over the lumps, and pre-
venting further decomposition by the acid. The water
should not be added too soon, or part of the cyanide
becomes dissolved, and gives a violent reaction. The
residue which remains in the dishes is buried, and the
dishes are washed in clean water before being again
used.
" Time necessary for Treatment. The cover is left
over the tree for thirty minutes in the case of small
trees, and forty-five in the case of those over twelve
feet in height. At the expiration of this period the
generating vessel is removed, and the residue buried in
the soil.
" A number of trees are fumigated together, the
endeavour being to treat as many at a time as can be
covered and uncovered during the period of exposure.
In this way the men are kept continuously busy, the
time for the removal of the first tent arriving by the
time that the last tree is covered.
" Absence of Sunlight necessary . The originators of
the fumigation process observed that the gas was most
efficacious, and that less injury resulted to the foliage
when the operations were performed at night than
when they were carried on in sunlight. It is said that
chemical changes are produced in the gas by the action
of sunlight, and that the resulting gases are more
injurious to the plant life and less to animal than
hydrocyanic acid gas. Whether or not these theories
are correct is of small practical importance, for the
foliage of a tree will suffer serious injury if the tree is
left covered with an airtight oiled tent for half an hour
in sunlight without the gas being present. Having
56 METHODS OF PREVENTION AND REMEDIES.
ascertained this fact by experience, the foreman in
charge of the Board's outfit refrained from covering
trees until the sun had sunk from sight on any but
cool dull days. The great majority of the trees treated
have been fumigated after sunset. The ideal night
for fumigating is quiet, cool, and moonlight, and
without dew."
From such valuable and trustworthy evidence ,i>
the foregoing we may safely take action with con-
signments of hard- wooded plants. But for such tender
things as orchids or other rare and costly plants
the process is likely to end in serious injury to them,
and cannot therefore be expected to find universal
favour amongst English horticulturists.* There is this
to be added, however, that all other fumigating com-
pounds have been found by Mr. Green less effectual
to Coccids and more injurious to plant life than the
hydrocyanic acid gas.
In the absence of fumigation or of the application <>\*
insecticides, which, owing to the nature and condition
of the plant, may be deemed inadvisable, a thorough
sponging with clean water should invariably be made.
All foreign substances should be removed, and the
plant or plants afterwards watched for any signs of the
development of scale or bug.
Coccids are also freely imported into this country on
oranges and lemons, including the troublesome and
* In the Journal of the South-Eastern Agricultural College, Wye,
Kent, No. 9, April, 1900, Mr. H. H. Cousins gives ;i report on some
excellent results obtained by fumigation of vines and greenhouse
plants with hydrocyanic acid. For inealy bug he recommends " 3| oz.
cyanide, 5 oz. acid, 8 oz. water per 1000 cubic feet, either before the
vines bloom, or when grapes are colouring, or after the crop has been
gathered. At either of these stages no harm results to either foliage
or fruit. Avoid fumigation when the vines are in bloom or before the
grapes have commenced to ripen," (1. c., p. 70).
" For ordinary greenhouse pests, such as aphis, dolphin, white-fly,
slugs, woodlice, red spider, and caterpillars, a dose not exceeding If to
2 oz. cyanide, 4 oz. acid, 7 oz. water per 1000 cubic feet has proved
itself satisfactory," (1. c., p. 70). In one greenhouse in which the
experiment was conducted there were chrysanthemums in full bloom.
Mr. Cousins says " not a petal or leaf was injured."
METHODS OF PREVENTION AND REMEDIES. 57
destructive Aspidiotus awrantii, etc. Care should,
therefore, be taken not to place infested fruit near to
growing plants ; and the rinds of all infested fruit
should be destroyed.
The encouragement of the various species of tits
(Paridae), the tree creeper, and other insectivorous
birds in our gardens is also a sure means of checking
the increase of certain Coccids, and their presence in
our gardens during winter should never be denied.
Their services at such times cannot be overrated, and
more especially so that of the little blue titmouse. I
am fully aware of the injury caused by these birds
to apples and pears; but in view of their excellent
services give them all the encouragement you can
afford. In winter encourage their presence by throw-
ing out an occasional handful of maize ; this will
attract them, and will generally keep them within the
bounds of your garden. When they have finished the