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INSECT DISPLAYS

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P1032

1958

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CANADA DEPARTMENT OF AGRICULTURE

Publication 1032

October 1958

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INSECT DISPLAYS

By A. A. WOOD
Entomology Laboratory
Chatham, Ontario

Science Service • Entomology Division
CANADA DEPARTMENT OF AGRICULTURE

EDMOND CLOUTIER, C.M.G., O.A., D.S.P.
QUEEN'S PRINTER AND CONTROLLER OF STATIONERY

OTTAWA, 1958

Price $3.00

54899-0 — 1

iC-23680-IO:53

Price $3.00 Cat. No. A43-1032

Available from the Queen's Printer

Ottawa, Canada

CONTENTS

Page

ILLUSTRATIONS iv

PREFACE vii

COLLECTING AND REARING INSECTS 1

PRESERVING IMMATURE INSECTS

Dry Mounts 2

Liquid Preserving 4

PRESERVING ADULT INSECTS 5

COLLECTING AND PRESERVING PLANTS

Collecting 6

Mounting 7

Preserving Green Colors 7

PLASTER MOLDS

Plaster — characteristics and uses 8

Preparing Molds 9

Plaster Slabs — preparation of 14

FLEXIBLE MOLDS

Latex Molds 14

Gelatin Molds 19

METAL MOLDS: FOR CASTING LEAVES IN PLASTIC

Constructing the Mold 19

Casting in Sheet Plastic 21

CASTING IN WAX

Fruit and Vegetables 22

Leaves and Petals 26

Larvae 28

Plaster Casts 28

CASTING IN PLASTICS

The Walters Method 28

Coldpress Casting of Leaves and Petals 34

Plastic Material for Cold Molding 35

Casting Foliage for Miniature Groups 36

Embedding in Plastic 36

PAINTING AND ASSEMBLING

Assembling Plant Parts 37

PRESERVING CONIFEROUS FOLIAGE 40

BUILDING INSECT DIORAMAS 48

Example: Exhibit of Wheat Stem Sawfly

— details of preparation 42

Animated Models 47

AIRBRUSH TECHNIQUES 47

BUILDING INSECT DIORAMAS 48

DISPLAY UNITS AND LABELS

Display Units 50

Labels 54

iii

Page

SHIPPING 59

FORMULAE

Preserving Larvae Dry 60

Preserving Larvae in Liquid 61

Preserving Adults 61

Alcohol: Uses and Diluting 64

Soldering 65

Preserving Leaves, Stems, Fruit and Vegetables in Liquid 65

Preserving Red in Fruits and Vegetables 66

Preserving Color in Plants for Mounting 67

Separators for Plaster Casts 68

Separators for Wax Casts 69

Base Construction (Maches) 69

Thinners for Airbrush Oil Painting 70

Preserving Natural Soil Units for Bases 70

Methods for Casting in Plastic 70

EQUIPMENT AND MATERIALS

Laboratory Facilities 71

Mold Making 71

Casting in Wax 72

Casting in Plastics 73

Art Work 73

Assembling Exhibits 74

Collecting Insects 75

Inflating Larvae 75

Collecting Plants 75

Preserving Plants 76

Miscellaneous 76

APPENDICES

A — Sources of Equipment and Materials 77

B — Supply Houses 79

C — References 80

D— Glossary 82

E — Index 85

ILLUSTRATIONS

Page
COVER — Cabbage insects, Plant reproduced in cellulose nitrate.

COLLECTING AND REARING

Figure 1 — Cage for rearing larvae 7

Figure 2 — Mounted herbarium specimen with label 7

PLASTER MOLDS

Figure 3 — Left, potato tuber in clay with dam. Right, first section with holes

drilled for keys 10

Figure 4 — Left, mold ready for second pour. Right, mold ready for third pour 10

Figure 5 — Open mold showing pouring opening and holes for holding staple... 10

Figure 6 — Tin forms for leaf mold 13

Figure 7 — Plaster mold of leaf 13

RUBBER MOLDS

Figure 8 — Rubber mold in plaster packet showing treatment of undercut

in a sugar beet 15

iv

Page

Figure 9 — Exhibit of injuries to sugar beets. The lower model was cast hollow
from the rubber mold illustrated in Fig. 8. (Displayed in Science
Service Building, Ottawa.) 15

Figure 10 — First stage in preparing a rubber mold. Left, tin on wood base
with wires for mounting tuber. Right, tuber mounted ready for
applying latex 16

Figure 11 — Left, rubber mold on tuber embedded in clay. Right, ready for

first plaster pour for the mother mold 16

Figure 12 — Left, mold ready for second pour. Right, with key holes for

third pour 17

Figure 13 — Left, plaster jacket complete. Right, rubber mold being removed

from the tuber 17

Figure 14 — Rubber mold of cabbage head filled with plaster for storage to

prevent shrinkage. Plaster jacket in sections 17

Figure 15 — Plaster casts showing one enlargement from a rubber mold 17

METAL MOLDS

Figure 16 — Impression in molder's sand from plaster mold of leaf 20

Figure 17 — Metal mold complete 20

Figure 18 — Metal mold being smoked to form a separator for the second pour 21

CASTING IN WAX

Figure 19 Exhibit of potato diseases. Tubers cast hollow from rubber molds.

(Displayed in Science Service Building, Ottawa.) 24

Figure 20 — Exhibit of insect and other injuries to potato tubers. Cast

hollow from plaster molds. (Displayed in Science Service

Building, Ottawa.) 24

Figure 21 — Exhibit of the apple maggot. Cast hollow from plaster molds.

(Displayed in Science Service Building, Ottawa.) 25

Figure 22 — Exhibit of some pests of the tomato. All in wax. (Displayed in

Science Service Building, Ottawa.) 25

Figure 23 — Wire and cotton on leaf mold ready to cast in wax 26

Figure 24 — Wax leaves. Left, as leaf comes from the press. Right, the edges

trimmed 26

Figure 25 — Rolling to thin the edge of a wax leaf 27

Figure 26 — Wax larvae cast in plaster mold 29

CASTING IN PLASTIC

Figure 27 — Upper, plaster waste mold speckled with ink to aid in applying

even coats of liquid plastic. Lower, plastic cast on the mold 30

Figure 28 — Exhibit of cabbage insects. In cellulose nitrate. (Displayed in

Entomology Laboratory, Chatham.) 32

Figure 29 — Exhibit of the eastern tent caterpillar. Foliage in cellulose nitrate;

branch in wax; larvae inflated empty. (Displayed in Forest Insect

Laboratory, Sault Ste. Marie, Ontario.) 32

Figure 30 — Exhibit of the spinach leaf miner. In plastic. (Displayed in Science

Service Building, Ottawa.) 33

Figure 31 — Exhibit of the tomato hornworm on tobacco. Foliage in cellulose

nitrate; eggs and larvae in wax. (Displayed in Science Service

Building, Ottawa.) 33

Figure 32 — Rubber mold for casting leaves in liquid plastic 35

Figure 33 — Cold-press casting in plastic. Plaster mold, plasticine, and cast leaf 35

PAINTING AND ASSEMBLING

Figure 34 — Compound leaf. Upper, potato leaflets soldered to central wire.
Center, leaf stalk modelled in wax. Lower, stem and midribs
masked, for spraying leaf blades 38

Figure 35 — Exhibit of insects on a hill of potatoes. Prepared in wax by casting

and modelling. (Displayed in Entomology Laboratory, Chatham.) 39

Page

PRESERVING EVERGREEN FOLIAGE

Figure 36 — Exhibit of the European spruce sawfly. Preserved foliage colored.
(Displayed in Forest Biology Laboratory, Fredericton, New
Brunswick.) 41

BUILDING ENLARGED MODELS

Figure 37 — Exhibit of the wheat stem sawfly. Models enlarged six times.
In cellulose butyrate. (Displayed at Permanent Canadian Exhibi-
tion, London, England for some time after 1949.) 43

Figure 38 — Tool for scribing striae on enlarged plastic models of wheat stems 44

Figure 39 — Left, enlarged pattern of section of wheat leaf. Right, model of

section in plastic 46

Figure 40 — Model of female of the wheat stem sawfly in plastic 46

AIRBRUSH TECHNIQUES

Figure 41 — Gauge for liquid carbonic acid gas outfit 48

BUILDING INSECT DIORAMAS

Figure 42 — Plan of diorama unit. Left, proportion of the base. Right, end

elevation 49

Figure 43 — Tools for modelling paper-based leaves. Upper, veining tool.

Lower, embossing tool 50

Figure 44 — Injury by the clear-winged grasshopper to Marquis wheat, and egg
bed in sod. Plants in cellulose nitrate. (Displayed in National

Museum of Canada, Ottawa. ) 51

Figure 45 — Grasshoppers emerging from sod, and control in wheat with
poisoned bait. Plants in cellulose nitrate. (Display in National

Museum of Canada, Ottawa. ) 51

Figure 46 — Plans of walnut display cases with glass tops 52

Figure 47 — Museum display unit 54

Figure 48 — Special display unit for a small exhibit 55

Figure 49 — Method of assembling plate glass in unit shown in Fig. 48 55

PREPARING PHOTOGRAPHIC LABELS

Figure 50 — The Coxhead-Liner photo-lettering machine 57

Figure 51 — The Coxhead-Liner Typemaster 57

Figure 52 — Gothic copperplate in the various sizes used 57

Figure 53 — Lydian cursive, actual size and reduced 57

Figure 54 — Proof of monotype, actual size 57

Figure 55 — Completed caption ready for photocopying 57

Figure 56 — Completed caption as used in exhibits 57

SHIPPING

Figure 57 — Shipping case with buffers of foam-rubber 58

EQUIPMENT

Figure 58 — (1) Scissors, (2) forceps, (3) scalpel, (4) combination knife,
(5) wax spatulas, (6) dental probe, (7) spoon and seeker, (8) dis-
secting needle, (9) holder for razor-blade splinter, (10) Swiss

pattern files 72

Figure 59 — (1) Proportional divider, (2) caliper, (3) micrometer caliper,
(4) dividers, (5) ruling pen, (6) swivel stencil knife, (7) flexible

spatula, (8) cutting forceps, (9) long-nosed cutting pliers 72

Figure 60 — Hand-press for casting leaves 73

Figure 61 — Tray of brushes in solvent for casting in liquid plastic; the stoppers

are fixed to the handles 73

Figure 62 — Airbrushes. Left, Wold. Center, Thayer and Chandler. Right,

Paasche 74

Figure 63 — Electric drill with flexible-shaft and grinder 74

Figure 64 — Cautery set and glass cannulae with spring clips for inflating larvae 76
Figure 65 — Plant press with driers and ventilators 76

vi

PREFACE

This manual outlines the various museum methods and procedures
that may be adapted for preparing entomological exhibits — a phase of
exhibition in museums that has not received a great deal of attention up
to now. Exhibits of insects, because of their small size, must be displayed
in small units for viewing at close range; the need for accuracy in all details
presents an important problem. Insects and plant sections must be so pre-
pared that each appears as a replica of the original.

Exhibition work in this field is highly specialized and requires wide
knowledge of art, entomology and botany, as well as many specialized
techniques. Accuracy of detail and lifelike quality are keys to successful
preparation of exhibits. The critical personal touch is necessary to remove
the stamp of mass production and raise them to works of art. Good mech-
anics alone is not enough; originality and inventiveness in tools, materials,
and design are needed constantly.

Many museum techniques developed through the years, especially
those involving the preparation of herbaceous units, may be adapted for
preparing insect displays. Success, however, depends on the ability of the
worker to employ these methods skillfully.

The author gratefully acknowledges the help and encouragement of
the following: Mr. Ramon Bermudez, and Mr. F. C. Schmid, Academy of
Natural Sciences, Philadelphia, Pa., the former for modelling and painting
wax casts, the latter for group building, backgrounds, miniature models,
paper leaves, and diorama lighting; Dr. James Chapin, Messrs. C. M. B.
Cadwalader, J. L. Clark, C. E. Olsen, and G. Petersen, and Miss Alice
Gray, American Museum of Natural History, New York, N.Y., for general
museum procedure, field collecting and care of specimens, diorama tech-
niques, celluloid casting, preparing plants in plastic paper, and coloring wax
casts; Messrs. Brayton Eddy and Earl Chase, Bronx Zoo, New York, N.Y.,
for field collecting, feeding, and exhibiting living insects; Messrs. H. H.
Clement, G. A. Linck, O. F. von Fuehrer, and Mrs. O. F. von Fuehrer,
Carnegie Museum, Pittsburgh, Pa., for useful materials and techniques in
group building, enlarged models, uses of latex in museum techniques, wax
casting and modelling; Messrs. Milton Copulos, W. J. Gerhard, J. H.
Quinn, Emil Sella, and L. L. Walters, Chicago Natural History Museum,
Chicago, 111., for molding and casting fruit, collecting and preserving insects,
rubber molds and plaster casts, plaster and metal molds, plastic casting and
assembly; Messrs. D. M. Blakely, James Carmel, and Walter Nickell, Cran-
brook Museum, Bloomfield Hills, Mich., for forest dioramas, enlarged
models, reinforcing base accessories; Messrs. C. E. Johnson and Clyde Patch,

vii

National Museum of Canada, Ottawa, Ont., for plaster molds, wax casts,
and group construction; Messrs. C. R. Aschmeir, W. L. Brown, and E. G.
Laybourne, National Museum, Washington, D.C., for plaster molds and wax
casting, group technique, and plastic casting; Messrs. H. Brooks, E. Keen,
and T. B. Pitman, Petersham Forestry Museum, Petersham, Mass., for back-
ground painting, the mechanics of miniature tree techniques, and the prepara-
tion of miniature forest groups; Messrs. T. B. Kurata, E. B. S. Logier, Archie
Reid, T. M. Shortt, L. L. Snyder, and L. Sternberg, Royal Museum of
Zoology and Palaeontology, Toronto, Ont., for enlarged models and painting,
airbrush technique and color blending, rubber molds and plastic casting,
gallery display, plaster molds and plaster casts, Dr. D. L. Gamble, Ward's
Natural History Establishment, Rochester, N.Y., for formulae; Dr. W. P.
Haynes, University of Illinois, Urbana, 111., for formulae; Dr. Carl D. Clarke,
University of Maryland, College Park, Md., for flexible molds and formulae;
Drs. A. A. Granovsky and G. H. Vacha, University of Minnesota, St. Paul,
Minn., for formulae for preserving fruit and vegetables; Dr. R. L. Post, North
Dakota Agricultural College, Fargo, N.D., for formulae; Dr. Alvah Peterson,
Ohio State University, Columbus, Ohio, for formulae for preserving insects;
Mr. John Gates, Science Service Laboratory, London, Ont., for taking photo-
graphs; and Mr. G. H. Parker, Bio-Graphic Unit, Science Service, Ottawa,
for contributing the section on preparing labels.

A. A. WOOD

vm

COLLECTING AND REARING INSECTS

In preparing an entomological exhibit, an insect net and killing bottle
are essential equipment. Beirne (1) gives detailed directions for collecting
and mounting insects for systematic collections. However, there will be
little need for standard mounting boards; insects used in exhibits are usually
mounted in lifelike positions.

Sometimes it may be necessary to rear larvae in the laboratory; netted
specimens of adult Lepidoptera, for example, often lose scales and are not
satisfactory for this type of display. This is one case where newly emerged
specimens should be used. Bring the larvae into the laboratory alive with
a supply of their host plant. Lantern breeding cages (Fig. 1.) for small
larvae can be made using sheet galvanized metal for the base and a shallow
metal can with a friction top with a hole in the center for inserting plant
stems in water. A lantern globe fits into a flange about f-inch high around
the top of the metal can. Enclose the top of the glass with cheesecloth or
screening. This type of cage will hold evergreens fresh for a week (see Fig. 1
p. 7).

Many larvae may be reared by placing foliage in large vials and loosely
plugging the openings with moist cotton. Almost any type of clean container
will do if it will confine the larvae, hold the food plant fresh, retain moisture,
and furnish sufficient space for proper expansion of wings. Insects that
pupate in the ground will need a layer of soil in the cages.

Refrigeration saves time in rearing insects and especially helps by
keeping food plants fresh. It retards surface drying, the main limiting factor
in keeping a supply of food. Fresh deciduous or coniferous foliage, layered
between sheets of wet paper towelling and placed in a covered crisper, will
remain in good condition for a week or two at temperatures a few degrees
above freezing.

Larvae of many insects held for making molds, inflating, or coloring,
can be kept in tight containers under similar conditions of temperature. The
last two instars of lepidopterous and hymenopterous insects stand refrigera-
ion better than younger larvae. Peterson (27) describes various breeding
cages and traps for insects.

PRESERVING IMMATURE INSECTS

Preserving insect larvae has always been a disappointing procedure.
Loss of color and form resulting from the various formulae used have dis-
couraged most workers from using larvae in exhibitions. Some larvae when
inflated hold their color very well but the form of most is undesirable when
conventional methods are used.

1

There are improved methods for preparing artificial insects but pre-
served specimens must still represent many forms in exhibits. Following are
some approved methods for preserving larvae.

Dry Mounts

With Formulae 1 to 3 (p. 60)* specimens may be mounted dry after
processing. Newly hatched larvae are difficult to preserve dry because shrinkage
is great; Formula 2 causes less shrinking than Formula 1. Larvae should
be preserved dry for exhibits only if it is impossible to make wax casts.

If Formula 3 (p. 60) is used, place larvae over one centimeter long in
cold water over a slow fire and remove the container when the water reaches
the boiling point. After the water cools to room temperature, puncture the
larvae in several places with a fine needle so that alcohol solutions will
penetrate.

Do not boil smaller larvae or pupae but place them in water at the boiling
point and leave to cool to room temperature then pass them through Formula
3. Larvae or pupae over one centimeter long should be left in each of the
solutions six to eight days, and smaller larvae or pupae two to six days. Then
take the specimens from the turpentine and let them dry on blotting paper;
mount as desired when dry.

Post (28) suggests the following method for dry-mounting larvae: boil
them one-half to one minute in water, remove, and pass through the alcohols.
Finally place them in xylol, then pin, and dry. This method preserves Phyllo-
phaga larvae better than Barber's method. Scarabaeid larvae should not be
boiled too long; they will suddenly deflate and resist all attempts to bring
them back to normal appearance.

Preserving Insect Eggs — Formula 1 or 2 (p. 60) may be used. When the
eggs are thoroughly dry, color tint them using pigment mixed in xylol,
turpentine, or white shellac. Do not use water because it will deflate the
specimen. Dipping the eggs in a very thin solution of Formula 45 (p. 70)
will impregnate them and make them rigid.

To preserve tent caterpillar egg masses place the twigs with eggs in an
oven at 225 °F. for 20 minutes. When the eggs cool, impregnate them
with a thin solution of cellulose nitrate, Formula 45 (p. 70), or Gelva V 15,
Formula 12 (p. 63). Cut off the twig near the egg mass. The shrinkage of
the twig will allow the ring of eggs to slide off. To assemble for a permanent
display, slip the egg mass over the prepared wax twig before it is built up to
full size and model wax around it.

Large insect egg shells may be preserved by blowing as with birds'
eggs. Make a small hole in one side of the egg with a small needle and with
a blowpipe — made by drawing a small glass tube to a fine point — expel the
contents. A short piece of rubber tubing attached to the end of the glass will
make the blowing operation less difficult. Hold the tip of the blowpipe
either near the hole in the egg shell or insert it slightly. Air forced into
the egg will empty the shell.

*The various formulae used for preserving insect and plant specimens are listed together
from p. 60 to p. 71 in the back to avoid repetition in the text. All will be referred to in
the text by number and page only.

Gunder (11) gives detailed instructions for blowing insect eggs using
T. M. Blackman's method. One useful point made in this article, is the
method of holding the egg while blowing it. If the egg is not attached to
something, a minute drop of adhesive can be used to fasten it to a piece of
paper. This frees the right hand to operate the blowpipe; the paper with the
egg attached is held with forceps in the left hand.

Inflating Empty Larval Skins — Living larvae may be used. First cut around
the anus, freeing the alimentary canal attachment then squeeze gently near
the opening to extrude the viscera; with the forceps, carefully remove all
body contents.

Place the larva between two pieces of blotting paper leaving the
caudal end exposed. Roll the larva gently, pressing at the middle to force
the body contents through the anal opening. Repeat the process, pressing
at the head until all fat and body fluids have been removed without enlarging
the opening in the skin. For all specimens except certain green forms, it is
most important to remove all the alimentary canal and contents. Some pale-
green larvae hold their color better if all body juices are not removed.

To dry the skin, Ross (32) suggests using a 250-watt infra-red lamp
with ruby red glass and a nickel reflector clamped on a stand. If the skin
is held about 2 inches above the center of the lamp and rotated it will dry
without scorching the integument or the setae. This process will not appre-
ciably alter the natural color.

If you use an inflating oven, heat it with an alcohol lamp. Insert the
cannula tip into the anal opening and either fasten it with clips or hold it
in place with forceps. If you use spring clips, apply vaseline to the glass
tip to keep the skin from sticking. Be sure not to pull the skin too far onto
the glass. Maintain just sufficient air pressure in the bulb to extend the skin
to natural size. One of the most glaring faults of this technique is over-
inflation which causes the segments to separate.

Turn the specimen constantly to ensure even drying. When the skin
has dried thoroughly remove the cannula. If the skin sticks to the glass,
great care must be taken not to tear it; a little moisture may aid removal.
After the skin has dried for a day or two, coat the inside with a thin plastic
lacquer, Formula 12 (p. 63), injected through the anal opening with a
hypodermic needle.

Inflating Larvae with Wax — A more recent method of preparing larvae for
exhibits consists of inflating the skin with hot wax; it is a modification of
the Silver (37) method. It has given better results than the standard pro-
cedure above in which the skin is left empty. This method has been used
successfully to prepare smooth-skinned species of dipterous, coleopterous,
and lepidopterous larvae and some of the sawflies.

Empty the skin as described above for inflation. Use larger cannulae
made from i-inch glass tubing. Fasten the watch spring clips to the tubing
with fine annealed wire. Melt a mixture of 1 part pure white beeswax and
2 parts paraffin wax in a double boiler. Tint the wax with artists' tube
colors, blended and thinned with turpentine to match the basic body color
of the larva. Draw hot wax into the cannula for half its length. When the

wax has cooled, slip the skin over the glass tip and fasten with clips. Attach
the cannula to the cautery set.

Hold the wax-filled end of the cannula over the inflating oven in such
a position that all the wax will liquefy without the larval skin becoming too
hot. Regulate the pressure in the bulb to force the wax into the skin, gently
filling it to natural size. Then immediately dip the specimen and the glass
tip in cold water.

Bend the specimen to any desired lifelike position as soon as you
remove it from the glass or place it in warm water until the wax softens
sufficiently. Do the shaping before the skin dries. Fill the hole left in the
wax by the cannula and shape the integument to a natural poise.

To pest-proof the skin, treat it with a weak solution of mercuric chlor-
ide, Formula 10 (p. 62). When thoroughly dry, dip it in a very thin Gelva
solution, Formula 12 (p. 63); this will seal and strengthen the specimen.
The skin should not show more than natural glossiness; usually two thin
coats give better results than one heavier one. After each dipping, roll the
specimen about on porous paper to get rid of excess plastic lacquer. If
the skin needs coloring, do this before treating with plastic.

Liquid Preserving

Specimens processed by the following methods must be kept in liquid
preservatives. Kahle's fluid, Formula 6 (p. 61), is used chiefly to preserve
larvae permanently.

Place the larvae in cold water and bring them slowly to a boil. Leave
them over the heat until the body begins to straighten, but not until the
segments separate. Allow the water to cool to room temperature before
transferring the larvae to the preserving fluid.

Craig's method of preserving color in larvae, Formula 5 (p. 61) appears
to hold some colors well. A series of fifth-instar larvae of the tomato
hornworm was successfully prepared by this method.

Post (28) offers the following method for avoiding bubbles in vials.
Form a blunt plug of good-quality absorbent cotton by twisting it between
the thumb and the forefinger. Saturate the plug with the solution and insert
it in the full vial. Fill the space above the plug and insert the cork. The plug
should fit the vial snugly. Any bubble formed between the plug and the
cork cannot reach the specimen.

To make sure corks remain firmly in vials, lay a fine insect pin along
the side of the cork as it is pressed in; this allows air to escape. Remove
the pin and twist the cork to fill the groove left by the pin. The cork will
be held in by the vacuum formed.

Preserving Larvae in Gelatin (13) — Kill the specimens by dropping them
into boiling water. Then place them in Formula 6 (p. 61) for 12 hours.
Wash the material in tap water until all traces of the odor of the fixative
have disappeared; this may take 24 hours. Keep in 3 per cent formaldehyde-
distilled water until ready to mount in gelatin.

Remove the specimens and allow them to dry for a few minutes on
a towel. Cut cards to fit the vials and attach the specimens with Duco cement.

4

Insert the mounts in the vials and fill with hot gelatin, which is prepared
as follows: Dissolve 5 gm. of bacteriological gelatin in 100 ml. of distilled
water. Heat until it becomes clear. Stir in 20 drops of 40 per cent formal-
dehyde. The solution hardens slowly. When it has set, cork the vials and
seal them with two or three coats of Duco cement.

Gelatin mounts are superior to mounts in liquid preservatives because
the specimens do not move around in the vials and there is little loss from
evaporation. The reaction of the gelatin and formaldehyde produces a per-
manent gel that will not melt in hot water. The jelly-like material in the vial
acts as a shock absorber for the mount.

PRESERVING ADULT INSECTS

Adult insects pinned and dried in the usual way will not last long in
exhibits. It is necessary to preserve them in such a way that colors will not
fade, that the specimens will remain free from pest attack and be strong
enough to withstand the vibrations of moving or shipping. A few of the
techniques used for preserving in color are briefly noted.

Lepidoptera — Large-bodied moths should not be dried and mounted in
exhibits without suitable processing. They are subject to attacks from pests
and become greasy. To avoid greasiness, cut a slit along the underside of
the abdomen and clean out thoroughly, removing as much fat as possible.
Swab dry with bits of absorbent cotton and apply arsenical soap, Formula
11 (p. 63), to the interior, working it up through the thorax. Insert a
manikin of cotton, filling the cavity. Mount the specimen in a lifelike posi-
tion and allow it to dry.

When the wings are in a position so that the bottom sides will not show
in the exhibit, coat the underside of the specimen with white shellac to
strengthen it; pay particular attention to the bases of the wings and the
undersides of the body, head, and leg attachments. Coat the antennae with
thin white shellac or plastic lacquer and apply a second coat to the bases.

To reduce fading of colors in moths and butterflies, paint the scales. It
is better to use fresh specimens but it is possible to restore faded ones this
way. You can probably do the finest work with an airbrush. Mount the
specimen on a base with supports against the undersides of the wings to
protect them from the blast of the airbrush. Use masks to work out the color
pattern, and spray. Claude E. Johnson, formerly preparator in the National
Museum of Canada, prepared a polyphemus moth by this method. This
specimen has held colors well although exposed to light for several years.

You may also brush in colors using the transparent oil colors for slide
and photograph tinting. Thin the pigment with xylol and allow it to run
into the scales.

Orthoptera — The following method can be used to preserve grasshoppers
satisfactorily. Immerse living specimens in Formula 8 (p. 62) for one day.
Cut along one lateral abdominal suture and remove all viscera with fine
forceps. Insert wads of absorbent cotton and rub the walls of the cavity
and up into the head until the swabs come away clean and dry. Brush

thinned arsenical soap, Formula 11 (p. 63), over all of the interior. Insert
a cotton manikin to fill the cavity.

Close the incision, mount in the desired position, and let it dry
thoroughly. Dip in a very thin Gelva solution, Formula 12 (p. 63), at
least twice which will impregnate and hermetically seal the specimen. Liquid
cellulose nitrate or acetate may be used, but has not the penetrating quality
of Gelva. This method holds the colors and greatly strengthens the specimen.

For green katydids, place freshly killed insects in Formula 8 (p. 62)
for one day and then treat them in the same manner as grasshoppers.

Coleoptera — With large beetles, remove the viscera through an incision
in the underpart of the abdomen. Insert absorbent cotton saturated with
arsenical soap, Formula 1 1 (p. 63). When dry, dip the specimen in thin
Gelva solution, Formula 12 (p. 63), to impregnate and seal.

Small Soft-bodied Insects — Use Formula 2, (p. 60), for insects whose
abdomens will remain plump. The method works well for larvae and midges
and other small, soft-bodied adults that are to be mounted in lifelike
positions.

COLLECTING AND PRESERVING PLANTS

The reproduction in wax or plastic of insect injury to plants often
makes it necessary to collect insect-injured plant series to be used as patterns
in copying the injury on artificial reproductions. The natural material may
be mounted as scientific specimens on botanical mounting sheets, or small
twigs and leaves may be mounted on filing cards and completely covered
with scotch tape.

Collecting

Choose plants typical of the species. Bend tall specimens several
times, or cut out sections of the stem to conform to the size of the mounting
sheets. Always leave roots attached. Be careful with the artistic arrange-
ment of plants before drying, so that the appearance of the finished mount
will be satisfactory.

Arrange the plant in the press as soon after collecting as possible.
Fold a sheet of porous paper, such as newsprint, and place the plant inside,
paying particular attention to arrangement of leaves and flowers. Place
the folded paper, with the plant inside, between driers in the press. Leave
the plant in the paper until dry, so that the driers may be changed without
disarranging the specimen. Pressure should not be too great when plants
are first put in the press; it may be increased when they become partially
dry and there is no danger of crushing soft parts.

After the day's collecting, if plants have been put in the press in the
field, re-arrange any parts needing attention. Place a few ventilators between
driers.

Figure 1

Cage for rearing
larvae.

Figure 2

Mounted herbarium

specimen with label.

The first 12 to 24 hours will determine the quality of the pressed plant.
Rapid drying preserves natural colors. Change the driers several times during
the first day or two as they absorb moisture from the plants. Used driers
may be dried in an oven or in the sun.

To hasten drying, place the press where there is good circulation of
air; leave it in the sun, or hang it over some source of heat.

Mounting

When the plant is thoroughly dry, mount it permanently on a botanical
mounting sheet. If the plant is not longer than the sheet, mount it straight
in the center; if it is longer, place the root toward the lower left corner
and the top diagonally toward the upper right. Attach the plant to the
mounting paper with narrow strips of mounting tape, using sufficient points
of attachment to hold all parts of the specimen. Attach the label in the
lower right corner (Fig. 2).

A useful method of mounting is to coat a sheet of glass with Gelva
solution, Formula 12 (p. 63), lay the specimen on and when it is well
coated on the underside transfer it to mounting paper. Advantages of the
method are neatness, strength, and the absence of mounting tape covering
parts of the plant. Should it be necessary to remove the specimen, acetone
will dissolve the adhesive.

Preserving Green Colors

In Liquid — Methods of preserving green colors in plants and foliage,
and also the various colors of fruits are given in Formulae 20 to 27 (pp.
65 to 67). Formula 20, the boiling treatment to replace the natural greens
with copper acetate, gives very good results when the specimens are stored
permanently in liquid.

Dry Preserving — Green colors may be preserved in plants by using
Formula 28 or 29 (p. 67). The specimens may then be pressed and
mounted.

PLASTER MOLDS

To reproduce plants and certain immature forms of insects in wax
and plaster, it is necessary to prepare molds of the originals from which
to make casts. The various plasters and methods of making plaster molds
are discussed.

Characteristics and Uses of Plaster

Calcined gypsum, commonly called plaster of pans, is calcium sulphate-
hemihydrate (2CaS04.H20). Variation in color of the gypsum rock
determines the shade of the finished plaster, which may vary from white to
gray. When water is added to calcined gypsum, it recrystallizes back to
hydrated rock. This chemical reaction produces heat in the plaster as it
sets. The heat of the mold indicates the time to remove it from the object
being treated. Each type of plaster has a definite setting time, which may
be controlled by adding accelerators or retarders to the water.

The plaster generally used in Canadian museums is Hammer Brand
Molding Plaster, formerly known as Hammer Brand FF, a Canadian brand.
The company states that this plaster is processed to the same specifications
as Red Top White No. 1 Molding Plaster of the United States Gypsum
Company. The latter company processes a wide range of plasters suitable
for different types of work which you may also buy from local dealers.
Some of these plasters are described below:

USG Red Top White No. 1 Molding Plaster — This is the standard form
of plaster of pans and is the general-utility plaster used in many casting
shops. The dependable uniformity in fineness of grinding and setting
characteristics makes it suitable for molds, plaques, and general work.

USG Red Top Superfine Gypsum Casting Plaster — This plaster has
a finer grain than the above, giving smoother castings and excellent detail.
It is ideal for modelling.

USG White Art Plaster — This plaster was designed especially for cast-
ings that are to be painted or that require a hardened, smooth-textured finish.
Adding a surface-hardening ingredient minimizes paint absorption yet
sacrifices none of the smooth-working qualities. To obtain the best and
most uniform surfaces, dry these castings rapidly in circulating warm air.
Trim and sand the castings before drying.

USG No. 1 Casting Plaster — This plaster was developed recently for
use when unusual surface density and hardness are desired.

USG No. 1 Casting Plaster (Special) — This plaster excels in structural
strength. A lower proportion of water is needed, giving greater strength
and hardness. Castings are uniformly hard from core to surface.

8

USG Pattern Shop Hydrocal Plaster — This plaster is moderately low in
setting expansion, giving accurate dimensions. The material sets gradually,
has a long period of plasticity, does not get too hard, and can be carved.
The normal mixture is 100 parts of plaster and 50 to 54 parts of water by
weight. Setting time is 20 to 35 minutes. The setting expansion is 0.00125.
Compressive strength dry is 3,200 pounds per square inch.

USG Hydrocal A-ll — This is a high-strength gypsum cement with a
low setting expansion and is suitable for making hard, tough models of
uniform and stable dimensional accuracy. It sets rapidly after the setting
actions begins. It is recommended for pouring or slurry casting technique.
The normal mixture of this plaster is 100 parts of plaster and 40 to 42
parts of water by weight. The setting expansion is 0.0004. When set, its
compressive strength is 4,500 pounds per square inch.

Coecal Plaster — Coecal plaster, a Canadian dental plaster, is excellent
for fine work. It takes only 1 part water to 3 parts plaster by weight
and has a compressive strength of 7,000 pounds per square inch after setting
for 22 minutes. To produce best results, the plaster should be sifted into
the water, allowed to stand one minute, then spatulated to a creamy
consistency. Vibrating the mix improves surface density and strength. It is
usually possible to remove a mold after 20 minutes. Coecal plaster is more
expensive than white molding plaster but it gives finer definition and allows
wax casts to free perfectly from the mold using only hot water as a separator.

Preparing Molds

Plaster may be used for molds, casts, and carved models, or as one
of the ingredients in mache when making bases. The proportion of water
in the mix affects the hardness, strength, density, and porosity of the mold
or cast. To obtain more uniformity in mold texture, precisely weigh or
measure the ingredients and carefully record notes on the results obtained.

Test for the correct amounts of plaster and water for particular plasters.
For example, a good technique for hard molds is to use as little water as
possible to form a mix that will pour. Whenever possible, it is best to use
the normal setting time for each particular plaster. If in special work
it becomes necessary to speed up or slow down the period of plasticity, or
free-flowing state, add accelerators or retarders to the mix. A little glue
added to the water will hold back the setting; common salt (sodium chloride)
or potassium sulphate dissolved in the water will cause plaster to set more
quickly. Accelerators in the plaster, however, will make molds more brittle.

A mold is like a photographic negative. It is made to obtain a negative
of an object from which to cast a positive, thus obtaining a detailed replica
of the original form.

Piece Molds — Those requiring more than one piece or section, must have
enough pieces so that the cast can be freed; undercuts in a mold will lock
the cast permanently.

54899-0—2

Fruit and Vegetable Molds — An apple, if not misshapen, usually releases
freely from a 2-piece mold. A potato tuber, however, because of its
uneven shape and deep eyes, requires three or more pieces. A material
is needed for shaping around objects before making molds; the best material
is water clay. A mixture of clay and sand that has gone through a brick
or tile machine works well; it is not too sticky. Storing clay in a tight
metal box with a little water in the bottom will keep it soft indefinitely.
The following method of preparing a piece mold of a potato tuber in
plaster will serve as an example. First if there is dust or soil on the potato skin,
wash it thoroughly. Decide which side is to show in the exhibit, and where
it will be best to join the several mold pieces and then:

1. Roll out a piece of clay to slightly more than half the thickness of
the tuber. Lay the tuber on the clay, keeping uppermost the side to be
featured in the exhibit. Mark on the clay around the tuber with a scalpel
point and cut out the section, leaving a cavity that will fit the tuber. Line
the clay cavity with thin, soft paper to keep it from sticking to the tuber.

2. Sink the tuber into the clay slightly more than half way. Model the
clay smoothly against it, being careful not to cut the skin.

3. Cut a strip of thin card about two inches wide and long enough to
reach around the tuber. Leave £ inch of clay all around between the card
and the tuber. Apply vaseline to the inside of this band, pin the overlapping
ends, and press it into the clay. This will act as a dam to contain the poured
plaster that will form the first section of the mold (Fig. 3, left).

Figure 3

Left, potato tuber in
clay with dam.
Right, first section with
holes drilled for keys.

Figure 4

Left, mold ready for
second pour.
Right, mold ready for
third pour.

Figure 5

Open mold showing

pouring opening

and holes for holding

staple

4. Pour water (about 4 ounces for an average tuber) into a flat
bowl and sift in twice the weight of plaster, more or less, depending on the
type of plaster used. Let it stand for one minute, or until the water seeps
throughout the plaster. Stir carefully to avoid trapping air bubbles until a
smooth, creamy consistency is obtained. Use a brush and apply a thin coat
of plaster over the exposed part of the tuber. This will avoid bubbles
when pouring the balance of the plaster to a thickness of about I inch.
Keep the plaster uniformly thick for each section of the mold. A thick area
of plaster is likely to form a chalky surface on the mold.

5. After the plaster sets (when it becomes warm), remove the paper
dam and the clay from the tuber which remains fast in the plaster. With
a i-inch bit, make six hemispherical cavities in the plaster around the
tuber to form keys for the next pour. This ensures perfect alignment with
other pieces of the mold (Fig. 3, right).

6. Apply a thin film of vaseline to the edges of the mold section,
working it well into the key holes. This acts as a separator for the next
pour of plaster. Pin a strip of card, with vaseline on the inside, around
the mold section, and insert a clay dam to expose half of the portion
of tuber that was not in the first mold section (Fig. 4, left).

7. Paint plaster over the exposed area of tuber and pour the second
section. When this section becomes warm, remove the paper and the clay
dam. Drill holes for keys in the newly exposed edge and apply vaseline.
Place a vaselined strip of paper around the mold making it ready for the
third pour (Fig. 4, right).

8. Pour the third section and when the plaster is warm trim all sutures
until clean lines appear at the joins. Release the mold from the tuber by
wedging a knife blade into the joins until they separate; the pieces can
then be lifted off.

For a subject that will be fastened to the back of a display unit, carve
a ^-inch hole through the underside of the mold for pouring the wax.
On each side of this hole, bore a small hole to carry a wire staple for
supporting the finished wax cast in the display case. Bind the two small
sections of the mold together with fine wire to protect the edges of the
join (Fig. 5).

Two-piece Leaf Molds — For leaf molds, Coecal plaster lasts longer and
gives better definition than white molding plaster. It takes only a small
amount of the material to face the molds; ordinary white plaster may be
used to build up the necessary bulk to give it strength and support.

To be efficient, leaf molds should fit a hand press (Fig. 6, p. 13),
used for casting and made of uniform size with tin forms. For molds 1\
by 5 inches by 2i inches high, cut two pieces of tin 151 inches long, one of
them li inches wide and the other 2\ inches wide. Cut a wood block to
the above mold measurements. With a mallet and a vise, bend each tin strip
separately around the block, overlapping the ends at the join (Fig. 6).

Select leaves with strong varietal characteristics, of normal size, and
as fresh as possible. Leaves will stay fresh for a week or more if layered
between wet paper in a tightly covered metal box and refrigerated at a few
degrees above freezing. To make the molds, roll out a sheet of soft clay,
cut it into pieces a little larger than the bases of the tin forms (do not use

11

54899-0— 2i

clay that is too sticky) and press a form lightly on the clay to mark the
area within which the leaf or leaves are to be placed. Apply vaseline to
the insides of the tin form.

When a single large leaf is used, place the petiole at one end of the
mold. If you are making several small leaves in one mold, arrange them
side by side with the petioles all one way. Model the clay under the leaves
to support their natural shapes. Do not press the leaf or leaves into the
clay but make sure all edges are in contact with it or plaster will run under
when poured. If the leaf surfaces are soiled with clay, swab them clean
with water. Place an elastic band or a cord around the narrower form,
press it evenly into the clay.

Paint Coecal plaster quickly over the leaf surface to exclude air bubbles.
Pour on about I inch of Coecal plaster and fill the form with white plaster
(small molds may be made entirely of Coecal). Just before the plaster
begins to set, stroke off the top level with the tin form.

Remove the plaster from the form after it has set. Remove the clay from
the leaf very carefully so as not to loosen any leaf surface from the plaster.
Should this happen, you must fasten the leaf to the plaster evenly or a
thick spot will result on the cast; thin a little bookbinders' paste with water
and slide it in between the leaf and the plaster with a fine brush. Press
the thumb on the leaf back of the loosened area to avoid lifting more leaf
surface.

See that all the leaf edges are free from plaster that may have run
under. Drill depressions for keys with a i-inch bit and apply vaseline to
plaster surfaces with which the next plaster pour will come in contact.

Apply vaseline to the insides of the 2i-inch-wide tin form and fit the
form around the first piece of the mold surrounding the leaf, to contain
the second pour of plaster.. Make sure the bottom of the tin form is even
with the bottom of the plaster block and tie the form with wire or cord
so that it fits tightly against it. Treat this second block the same as the
first; after levelling the top, let stand until it sets.

When the plaster becomes warm, remove the tin, trim the join if
necessary, and tap the mold along the join so that it may be pried apart
with a knife. Remove the leaf from the mold, wipe any bits of plaster
from the face, and bind the two halves together with fine wire to dry (Fig. 7.).

To make plaster molds for thin leaf casts, especially when the undersides
will not show, use the following procedure. Remove the leaf from the mold
piece after the first pour. Paint the plaster surface with a separator,
Formula 32 (p. 68). Place the wide tin form in position and finish as
described above. Cut a groove for the midrib wire in the under half of the
mold.

Molds of Larvae — Thoroughly remove chemicals from preserved larvae
before molding. It is much better to use living larvae; any distortion in a
preserved one will show in the mold. One of the difficulties is to keep the
specimen from collapsing while making the mold. To obtain best results
with large larvae, place the living larvae in cold water, bringing them slowly to
a boil. Allow the water to cool with the larvae in it. Injecting absolute
alcohol hypodermically through the anus will also harden the larvae. Very
small larvae are best killed with ether.

12

Coecal dental plaster works well for molds of larvae. Cut a narrow
strip of thin cardboard, apply vaseline to one side, overlap the ends and pin.
Shape this dam so that it will surround the larvae evenly, and press the edge
of the paper into a smooth piece of clay or plasticine. Pour plaster to fill
the dam and level off the top, teasing any surface bubbles to the edge with
a pin. With forceps, pick up a larva and, beginning at the caudal end,
carefully lay it on its back in the plaster, sinking it evenly halfway. With the
point of a pin, even the plaster where it touches the sides of the specimen.
Allow the plaster to set, remove the paper dam, trim the plaster where
necessary, and drill holes for keys.

Paint a thin film of vaseline on the mold edge and pin another dam
around the mold. It is now ready for the second pour. Cover the larva
with a thin coat of plaster, blowing to rid the surface of bubbles, and then
pour the rest of the plaster; alternatively the larva may be painted lightly
with thin plaster and the pour made.

Figure 6

Tin forms for
leaf mold.

Figure 7

Plaster mold

of leaf.

13

When the second pour has set, separate the mold by wedging it
apart with a knife. Scribe a fine channel with a scalpel point from the head
to the edge of the mold to allow air to escape when injecting hot wax.
Carve a funnel-shaped opening in the caudal end of the mold for injecting
the wax.

Preparing Plaster Slabs

Use two pieces of plate glass and four spacer blocks of the required
thickness. Mix plaster free of bubbles and to creamy consistency. Pour the
plaster on one of the pieces of glass, to slightly more than the thickness
desired. Make a high ridge down the middle so that the second piece of
glass, when pressed on the plaster until it rests on the spacer blocks, will not
trap air bubbles. No separator is needed. Allow the plaster to set fully
before sliding the glass off. Cut and shape the slabs soon after freeing.
When dry, they may be impregnated with thin Gelva solution, Formula 12
(p. 63). These slabs are useful for mounting small insects and showing
life histories in exhibits.

FLEXIBLE MOLDS

Latex Molds: Description and Uses — Latex is made from the milky juice of
rubber trees. For molds, natural latex is processed in such a manner that
it will dry or vulcanize without heat. It is one of the best mediums for
flexible molds, giving even better definition than plaster. Another advantage
over plaster is the absence of troublesome flanges resulting from joins.
It is not always possible to eliminate the flanges on wax casts made from
plaster molds; with rubber molds the only openings are at the back where
they do not show.

Preparing the Latex Mold — The following is the procedure for preparing a
latex mold of a potato tuber. Prepare a base on which to mount the potato
tuber. The tuber needs to be mounted so that all the skin is exposed; the
latex must not be touched with the fingers when it is drying. For a
medium-sized tuber, cut a piece of galvanized iron sheeting 2 by 2f inches.
Trim one end to conform with the contour of the underside of the tuber.
Bend the opposite end of the sheet to make a right-angled flange i inch
wide. Tack the sheet to a wooden block big enough to hold the tuber
firmly when mounted on the tin.

Cut two pieces of 1 8-gauge wire 2 inches long, and solder them vertically
to the free end of the tin; keep them I inch apart and projecting I inch above
the tin. Besides acting as a support for the tuber, these wires will leave two
holes in the mold for receiving a wire staple when casting; it is used to fasten
the cast in a display unit.

To complete the base, cut a f-inch cork stopper in half lengthwise
and fasten one half to the metal between the wires with Duco cement.
Leave the small end up and trim to fit against the tuber. The cork forms

14

INJURIES TO SUGAR BEETS

y

WIRFWORM

MEADOW K

Figure 8 — Rubber mold in plaster jacket- showing treatment of undercuts in a sugar beet.

Figure 9 — Exhibit of injuries to sugar beets. The lower model was cast hollow from the
rubber mold illustrated in Fig. 8 (Displayed in Science Service Building, Ottawa.)

a hole in the bottom of the mold through which to pour the casting medium
(Fig. 10, left). Press the two projecting wires into the tuber until the
metal sheet comes in contact with the skin, but without cutting it (Fig. 10,
right).

Use only a 1 per cent aqueous solution of ammonia for thinning; do not
dilute latex unless it is necessary to pour or spray it. Between coats,
brushes may be left in the ammonia solution or in a 10 per cent solution
of soap flakes in water. After applying the coats of latex soak the brush
in carbon tetrachloride and remove the latex by scraping should it become
filled with partly dried rubber.

No separator is needed when applying latex to a potato tuber; it is
applied directly to the tuber. Six coats should be sufficient depending on
the thickness of each.

Apply the first coat evenly with a soft bristle brush or your finger over
the entire surface, and about one inch down the tin and the cork. Drying
time between coats depends on the thickness of the coat applied. To
determine when to apply the next coat, press a hard object into the drying
latex. If the impression disappears, the rubber is dry. Should the mark

15

remain, let the rubber dry longer. Apply additional coats similarly, making
each coat even with your finger. Allow two or three days for final drying;
pull out the wires and the tin, leaving the tuber on the mold.

The next step is to prepare a plaster jacket, or "mother mold". This
is a 3-piece jacket to support the latex mold for casting in it. Cover the
mold with moist tissue paper and with the pouring hole at the top and the
tuber still inside, embed the mold to half its depth in moist clay (Fig. 11,
left). Cut a strip of thin cardboard wide enough to be level with the
highest part of the mold when the cardboard is pressed into the clay. Apply
vaseline to the inner side of the carboard, overlap the ends and pin to form
a ring large enough to expose f inch of clay all around the mold. Push the
cardboard into the clay. Cut a thin strip of clay and press it upright against
the mold to act as a dam to retain the plaster when poured on half the
surface of rubber above the clay base. It is now ready for the first pour
(Fig. 11, right).

Pour the plaster. When it sets, remove the paper containing-ring and
the clay dam. Bore four hemispherical holes in the edge of this section of
the plaster mold and apply vaseline as a separator. Place a strip of vaselined
paper as before around the rubber mold (Fig. 12, left). Pour the plaster
for the second section. When it has set, remove the strip of paper and peel
off the clay. Drill holes as before in the edges of the two sections and apply
vaseline as a separator (Fig. 12, right).

Place a paper dam around the mold, exposing the rubber that has not
yet been covered. Pour the plaster for the third section. When it sets,

fi ppg ' \* .pp*

Figure 1 0

First stage in

preparing a rubber

mold.

Left, tin on wood

base with wires

a^^^

■ "^

for mounting tuber.
Right, tuber

mounted ready for

^^^Hu

,fF

<m!

, ^^

■

applying latex.

rid]

—

Figure 7 7

Left, rubber mold
on tuber embedded

'"*

in clay.

1

Right, ready for
first plaster pour for
the mother mold.

w

jm 1

m .

_

MM

Figure 72 — Left, mold ready for second pour. Right, with keyholes for third pour.

Figure 13 — Left, plaster jacket complete. Right, rubber mold is removed from tuber.

Figure 14 — Rubber mold of cabbage head filled with plaster to prevent shrinkage in storage.
Plaster jacket in sections.

Figure 75 — Plaster casts showing one enlargement from a rubber mold.

remove the rubber mold (which is still on the tuber) from the plaster
jacket. The rubber mold and the plaster jacket are now complete (Fig. 13,
left). Dust talc over the outside of the rubber to prevent it from sticking
while it is being removed; this is important. Remove the mold from the
tuber (Fig. 13, right).

Place the two small sections of the plaster jacket together over that
part of the rubber mold on which they were made. Fasten the plaster
sections together by bending a wire around them. Fit the large plaster
section into place taking care not to buckle the rubber. Then with a wire
around the whole jacket, fasten it together. If storing the mold, fill it with
liquid plaster to avoid shrinkage (Fig. 14).

No reinforcements are necessary for small rubber molds. Pre-shrunk
flannel or absorbent cotton is best for medium-sized molds and moistened
burlap for large ones. When casting mache from a rubber mold, moisten
the face of the mold with water to which has been added 1 per cent water
softener, a detergent. Separators are needed when casting latex positives
from latex negatives. To prevent sticking, dust talc on the face of the mold
or apply shellac.

Do not use oily lubricants on an object from which a latex mold is to
be made; latex swells if added over oil. Latex molds last about 10 years
if properly stored. Keeping them in a cool, dark place adds to their useful-
ness. They shrink some and become hard in 15 to 20 years.

17

Reid (31) has recently perfected a new method of preparing latex
casts from plaster molds. Latex called CA-132 is thoroughly mixed with
filler CA-132, and allowed to stand twelve to twenty-four hours to rid the
mix of air bubbles. Increasing the proportion of latex results in a rubbery
casting: increasing the proportion of filler produces a heavier more rigid
casting. Plaster piece-molds are made in the usual manner, having the
pouring hole at the highest point. Place a ring of clay around the hole
to form a reservoir and make an air hole just outside this ring.

The moisture in the casting material is absorbed into the plaster mold,
drawing with it fine particles of the latex compound which are deposited
upon the face of the mold, giving perfect detail. These build up on each
other, and in about thirty minutes form a skin about ^ to -^ inch thick
(which is sufficient for most castings). Keep the mold filled until the desired
build-up is attained on the face of the mold.

Clean any partly-set casting material from the pouring hole and the
air vent. Pour out the remaining liquid part of the casting compound and
store if desired for future use. Invert the mold to drain overnight then pry
it apart, leaving the cast in one half of the mold. The cast is quite rubbery
at this stage and is easily deformed if handled. If this occurs, restore its
shape by blowing gently through the pouring hole. Allow the exposed
surface of the mold to dry for about four hours before removing from the
other half of the mold. Suspend the cast by a string tied around the pouring
nipple for twenty-four hours to dry completely.

This latex may also be used for preparing rubber molds by von
Fuehrer's method. Von Fuehrer (45, 46) also had instructions mimeographed
dealing with construction and uses of flexible molds in which he described his
discovery of a method to enlarge rubber molds.

Enlarging Rubber Molds — Enlarging rubber molds by soaking them in
oil makes it possible to obtain enlarged casts of various objects, keeping
details and proportions correct. Use of this procedure rather than the
usual method of preparing enlargements by modelling would save much
time.

To enlarge a rubber mold submerge it in kerosene for 24 hours, or
until it distends fully. If it is removed from the oil before it distends
completely, the proportions will not be correct. The degree of enlarge-
ment at one time is about 60 per cent. Rubber molds treated with heavier
oils lose their toughness and tear easily. If kerosene, gasoline, or carbon
tetrachloride is used for enlarging, the enlarged mold retains more of its
original strength.

By the time the mold has fully enlarged it has lost its elasticity and
acquired a metallic quality, but is still tough enough to use. Drain all oil
from the mold and place it in cold water to become more rigid.

Casting in Plaster from Enlarged Molds — The mold shrinks when
removed from the oil bath. Casting materials should therefore be ready so
that casting may be done as quickly as possible. Pouring fine sand around
a very small mold may hold it in shape but larger ones may need a thin
coat of quick-setting plaster poured on the outside.

18

Do not apply the first coat of plaster with a brush but flow it into
place because the mold is very tender. Be careful not to trap air bubbles
in the plaster. A second rubber mold may be made over the plaster cast
and be enlarged by the same method. This technique of enlarging the
rubber mold and casting in plaster may be repeated until the desired size
of model is obtained (Fig. 15). The larger the rubber mold, the thicker
it must be.

A rubber mold may also be enlarged by dipping it in benzene, and
then exposing it to benzene fumes by placing it on a glass platform just
above the liquid in a tight jar. This method gives about 50 per cent
expansion in six to seven hours. Contraction, however, is more rapid
than in the kerosene-enlarged molds. Have the casting plaster ready to use
immediately when the mold is removed from the benzene jar.

Gelatin Molds — This is a quick method of preparing a flexible mold when
only a few casts are needed. It produces fine detail and may be used over
a rough, uneven subject.

Fasten the object over which a mold is to be made to a base so that
it will not float when the mold material is poured over it. To contain the
getatin as it is poured, make a form of cardboard around the model, suffi-
ciently rigid to hold its shape and place. Leave a space of about I inch
between the form and the subject. Use casting gelatin that is sold to
plasterers for making ornamental molds.

Wet the gelatin in a 90 per cent water and 10 per cent gelatin solution
by weight adding as a preservative 1 per cent of zinc sulphate or 1 fluid
dram of phenol per gallon of gelatin. Use 10 to 20 per cent of the liquid with
the gelatin by weight. When thoroughly wetted, heat it in a steam- or a
water-jacketted kettle to not over 140° F until the gelatin has melted.
Before pouring, raise the temperature until the gelatin liquefies. Allow time
for bubbles to rise, skim them off and pour the gelatin over the subject
filling the form.

When the mold has cooled, remove the cardboard form and slit one
side of the mold to release the subject. With a soft brush, carefully paint
on two or three applications of 5 per cent formaldehyde solution if hot wax
is to be used in casting. Formaldehyde-hardened gelatin cannot be
remelted.

Make a removable plaster jacket around the mold and obtain desired
casts as soon as possible; formaldehyde will act on the gelatin and make
the surface granular in a few days.

METAL MOLDS: for casting leaves in plastic

Metal molds are sometimes used in casting deciduous leaves in plastic.
The technique of making and using such molds is discussed briefly. As with
plaster, metal molds may be made of one or both leaf surfaces.

Preparing Impressions of Both Leaf Surfaces — Make a 2-piece plaster mold
as described for leaf molds (p. 11). Prepare a wooden frame without a
bottom, about one inch longer and wider inside than the mold, and as
high as the double mold. Place one section of the plaster mold on a sheet

19

Figure 7 6

Impression in molders'
sand from mold
on leaf.

of glass, with the leaf impression up, and arrange the wooden frame around
it, leaving equal spaces on all sides. Use fine molders' sand. Moisten the
sand enough that it will hold together when pressed between the thumb and
finger, yet will still crumble. Sprinkle sand on the face of the mold and
fill in around it, packing tightly. Press the sand firmly into the plaster
impression and continue packing in sand until the frame is full. Scrape the
top level with the frame. Holding the frame and the glass together, turn
them over and slide the glass off. Remove a little sand at the edges of the
mold and lift it out carefully without disturbing the impression (Fig. 16).

The sand impression is now ready for the first pour. Babbit metal or
antimonial lead may be used. Babbit metal is cheaper and gives good
results. Heat the metal in an iron ladle over a gas flame but do not let the
metal become too hot; some of the alloy will be burned out and the mold
will show porous areas on the surface. Skim off the sludge. Test the molten

Figure 7 7

Metal mold
complete.

20

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metal for casting temperature by dipping
a piece of white paper into the melted
metal momentarily. The paper should not
burn, but turn yellow. Be careful that no
free water comes in contact with the
molten metal or it will explode. Pour the
metal on one section of the impression,
beginning carefully at the base and filing
the cavity left by the plaster mold.

Let the metal cool and remove it
from the sand. Repeat the above opera-
tion with the other section of the plaster
mold and the two sections of metal
will fit together as did the plaster mold
(Fig. 17).

Caution: Any disturbance of the
impression of the plaster mold in the
sand, before or during casting, will prevent
the two pieces of the metal mold from
fitting together.

*\

Figure 18 — Metal mold is smoked to
form a separater for the second pour.

Preparing Impression of One Leaf Surface

— Make one half of the metal mold
exactly as described above, using the
section of plaster mold of the desired surface.

When it is cold, smoke the impression surface by holding it over a burning
cotton cloth previously saturated with turpentine (Fig. 18) This will act
as a separator when the pour for the next section is made.

Cut a strip of asbestos paper twice as wide as the height of the
metal section and bind it around the metal, leaving the smoked impression
up. The asbestos will contain the molten metal until it cools. Be sure the
metal section is cool and dry; then pour the metal, filling the asbestos ring.
Never pour molten metal on a hot mold surface because it will stick.

Casting in Sheet Plastic from Metal Molds

Metal molds will not give the minute detail obtained by casting liquid
plastic from plaster molds. However, where large numbers of leaves are
needed, as in group exhibits, casting sheet plastic from metal molds is fast
and useful.

Casting Plastic Leaves from a Cold Metal Mold — Use molds that have
been prepared by the method described under the above heading "Preparing
Impression of One Leaf Surface".

Cut a piece of sheet cellulose nitrate, .005 or .001 inch thick and
slightly larger than the mold. Place it in a cold bath, Formula 46 (p. 70).
When the sheet becomes rubbery, remove and wash it quickly in cold
water. Quickly remove all water, using absorbent cotton. Complete
removal of water is important to prevent defects in the cast. Place the sheet
between the two halves of the mold, with the keys matching, and clamp the

21

mold in a vise until the plastic has set. Fifteen minutes or more are neces-
sary. Trim the edges of the impression. If it is difficult to follow the edges
on the clear cast, spray paint lightly on one side to bring out the detail.

Casting Plastic Leaves from a Hot Metal Mold — Use iron tongs to hold
the two halves of the mold together to keep the section in alignment and act
as a handle to remove them from a boiling water bath. Tongs must be
large enough to fit either end of the mold when the two sections are together.
Solder the jaws of the tongs to the mold sections while the mold is closed
and the keys registering perfectly. Cut a piece of sheet cellulose nitrate or
acetate slightly larger than the mold, and place it on the leaf impression.
Over this lay a piece of thin rubber (cut from a tire inner tube to the size
of the plastic sheet) place the other half of the metal mold in position and
clamp the mold shut. Place a ring tightly over the ends of the tong handles
to hold the mold shut. Immerse the mold in boiling water until the plastic
becomes soft. Then clamp the mold in a vice for ten seconds, change ends
and clamp again. Glycerin in a double boiler with sand in the bottom sec-
tion of the boiler will provide greater heat.

Casting Plastic Leaves from a Metal Mold in a Hydraulic Press — A

hydraulic press with controlled pressure from 10,000 to 30,000 pounds per
square inch is needed. Leaf casts of good detail are rapidly produced. Tool
out a channel for the midrib wire in the under section of the mold, place
a wire in the groove and put the mold on a hot plate. Place tenite plastic
in sheet or granular form over the impression in the mold over the wire,
close the mold and position in the hydraulic press. While in the press,
the plastic becomes softened to such a degree that it flows into all details.
The wire for the petiole and midrib will be firmly embedded in plastic.

CASTING IN WAX

Casting in wax plays an important part in preparing exhibits. Fruit,
vegetables, and the larvae of insects reproduced by this method are more
lifelike than when cast in plastic or plaster. Foliage also may be successfully
cast in wax; fewer molds are needed because it is possible to alter the shape
of casts after they are made. Casting in wax involves making a mold or
negative of the original object and pouring wax into it to obtain a positive.

Fruits and Vegetables in Wax

The proper separator to release wax casts from plaster molds should
be chosen. No separating agent is needed for molds made with Coecal
plaster heated in water but one should be used for white molding plaster.
Use Formula 37 (p. 69).

Melt pure, refined white beeswax in a double boiler. Turn the heat
to low when the wax has melted. Tint the hot wax by thinning tube oil color
with turpentine and stirring it into the wax. Formerly balsam was added to
beeswax to temper the casts and make them less brittle; but, contrary to
expectations, as the casts aged the balsam-treated wax became more brittle
than untreated wax. Before casting, check the following points and little
difficulty should arise: adjust the room temperature to 80° F, and the wax

22

temperature to 158° F; soak the plaster molds for at least 30 minutes in
water held at 128° F. If the molds are made of white plaster, add the soap
solution a few minutes before casting. Have a supply of special staples
ready to anchor one in each cast. For a small cast such as of an apple or
a potato, make the staple from a 3-inch piece of 18-gauge wire (bend the
ends at right angles to the center part). The crosspiece of the staple should
be i inch long. Apply shellac to the crosspiece and bind cotton around it.

Casting Solid^To cast, remove the mold from the hot water and swab
the inside with cheesecloth dipped in hot water and wrung out. Insert the
prongs of the staple from the inside of the mold through the holes pre-
pared to receive them, leaving the cotton-wound crosspiece projecting into
the mold \ inch or more to make sure that the staple will be well anchored
in the cast. Assemble the mold hot and, with a ladle large enough
to fill it in one pour, fill the mold. It is usually necessary to add a little
wax as it cools.

Casting Hollow — The procedure for casting hollow is the same as for
making a solid cast up to the time the mold is filled with wax; wait a
moment and then pour out nearly half. A good way to judge the quantity
removed is to pour it back into the ladle. Stop the hole with a cotton plug
held by the thumb and rotate the mold in every direction; the wax will cool
in an even layer over the entire mold. Open the hole from time to time
during the early part of the rotation to allow heated air to escape. Continue
rotating for a short time after no liquid is heard when the mold is shaken.

Release solid or hollow casts when the wax has set but is still rather
warm. Remove the wire holding the mold pieces and pry the pieces apart
slightly with a knife to loosen them from the cast. If a small cast sticks in
a piece of the mold, hold the cast in the hand between thumb and fingers
and just above the palm. Tap the mold gently with a wooden mallet or a
small hammer; this will usually release the cast. A slight flange is left on
the cast where the mold pieces join. Remove this while the wax is still
warm, with a spatula, modelling tool or other instrument. If any disfigure-
ment remains, dip your finger in carbon tetrachloride and rub it along the
tooled area. Do not remove any wax from either side of the flange. Rest
the cooling wax cast on two wooden blocks, with the staple between, until
the wax is cold.

To make a hollow cast that will be viewed from all sides, fill one half
of the mold with wax and replace the other half. Rotate until the wax sets.
Even with this method it is necessary to make a small hole in the mold
which you can open occasionally to release hot, expanded air; otherwise it
will force its way out between the joints and ruin the cast.
Causes of Difficulty in Casting in Wax

• If the cast sticks to the mold, the wax or the mold is too hot or the
mold has not been thoroughly soaked.

• If there are cracks in the cast, a draft chilled the mold on one side
while the wax was cooling.

• Pits in the surface of the cast are caused by droplets of water left on
the mold.

• If there are waves on the cast, the mold or the wax has been too cool,
or the wax has not been poured fast enough.

23

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54899-0—3

Leaves and Petals in Wax

Presses are used to make leaves in wax by pressure. To reproduce
a branch in wax, it is not necessary to use as large a series of leaf molds as
for casting in plastic. You may choose a few sizes and alter their shapes
after casting.

The press discussed is essentially the same as that described by Rowley
(35) except that the handle hinge has been changed to eliminate excess
sliding of the top section of the mold when the lever is worked (Fig. 60,
p. 73).

The sub-base is 4i by 12 by I inches. On this is screwed the base,
3i by 10 by li inches. The basal ends of two y^-inch drill bits, are
sunk into the base, allowing the tapered butts to project f inch. Two i-inch
bolts come up through one end of the base.

The upper lever is made adjustable to fit molds of varying thicknesses
by hinging it to a block of the same thickness (li inches) which works
up and down on the two i-inch bolts. Four wing nuts on the bolts regulate
the height. Pointed bolts on each side of the lever hold the upper half
of the mold in place. A template of sheet metal fits over the two drill
points in the base. This template is used when boring holes in the bottom
of the mold.

To adjust the press, place the mold on the base with the two drill
points fitting into the holes. Lower the lever, with the mold between the
two horizontal bolts, and adjust the wing nuts until the lever rests evenly
on the mold. Tighten the two bolts on to the sides of the mold while holding
the lever down tightly with the chest.

Taper wires for the midribs by tying a number together and dipping
the tips in acid for a moment; use hydrochloric acid for iron wire and nitric
acid for copper and monel wires. Tin copper wires or verdigris will form
on them. After dipping the wires in acid, wash and dip them in molten
solder. Wipe them quickly with waxed cloth to smooth the solder. A

Figure 23 — Wire and cotton on leaf mold Figure 24 — Wax leaves. Left, as leaf
ready to cast in wax. comes from the press. Right, the edges

trimmed

26

Figure 25

Rolling fro frhin the
edge of a wax leaf.

section of metal pipe will hold solder at melting temperature over a gas
jet. Dip the wires in shellac and cover them thinly with absorbent cotton.

Keep the room temperature at 85° F, the wax at 162° F, and the water
for soaking molds at 130° F. Such high temperatures are necessary in casting
leaves because the thin film of wax cools much more rapidly than the bulk
wax poured in casting heavy objects. Soak the molds in hot water for 30
minutes, remove, and blow the moisture off the faces of the mold. Fasten
the mold in the press. Lay a thin film of cotton over the midrib groove,
with the fibres crosswise. Place the wire in the midrib groove with about
one third of its length from the base and over the cotton. Apply another
sheet of cotton over the entire impression, keeping it away from the keys and
the edges of the mold beyond the impression. Use a maximum of cotton
(Fig. 23). Quickly pour hot wax over the cotton and immediately bring down
firmly the lever with the upper half of the mold. Raise the lever and usually
both halves of the mold will come up together. If they do, pry them apart
and remove the cast (Fig. 24, left). Before casting the next leaf put the mold
back in hot water or close it on a pad of cheesecloth previously soaked in
hot water.

As it comes from the press the cast leaf has a waste margin which must
be trimmed. Trimming is simple for leaves with a plain edge but one that
has serrations must be carefully notched as in the cast. Different edges
require different methods in shaping, but the pattern must be followed exactly
using fine scissors, razor-blade splinters (narrow cutting edges of the blade)
in holders, or a warm notching tool. Make all cuts firmly against the
impression; any parts of waste edge left will show especially if the leaf is
sprayed for colour (Fig. 24, right).

Thin the cut edge of the leaf with a modelling tool, either a small wooden
cylinder rounded at the end or the head of a hat pin. The latter tool is more
apt to cause gloss (Fig. 25.).

Causes of Difficulty in Casting Leaves in Wax

© If casts stick to the mold, the mold has not been thoroughly soaked, or
the mold or the wax was too hot.

• If casts are imperfectly filled out, too little wax was poured on the mold,
or the cotton was wet.

27

54899-0— 3j

• Pits on the cast surface are caused by some water left on the mold.

• If wires pull out, the cotton was not firmly attached to the wire with
shellac, or the cotton on the wire was wet.

Larvae in Wax

Immerse the molds in hot water for thirty minutes with the water
temperature at 130° F. Heat the wax to 160° F; it cools much more rapidly
when small amounts are used. Hang a pipette in the hot wax. Remove a
mold from the hot water, blow water from the inside, and fit the two halves
together, holding them tightly between thumb and fingers. Take up enough
wax in the hot pipette to fill the mold, and inject it quickly. Release the cast
in a very few minutes. Before the wax cools, carefully remove the funnel-
shaped piece of wax on the pouring end of the cast (made by the injection
opening) and the flanges on the sides. Use a lens for final shaping (Fig. 26.)
Some casts of larvae may be improved by removing the head and substituting
natural ones that have been dehydrated and impregnated with wax by boiling
gently. A portion of the skin with the six legs may also be used in this way.

A Note on Plaster Casts — If a separator, Formulae 32 to 36 (pp. 68 and 69),
is used, it is possible to release plaster casts from plaster molds that have
no undercuts. Plaster casts are easily chipped, but you can strengthen them
in a thin solution of Gelva, Formula 12 (p. 63).

CASTING IN PLASTICS

The Walters Method

Description and Uses — The plastic used is cellulose nitrate or cellulose ace-
tate. Both celluloids are inflammable but the nitrate requires greater care in
this respect; the acetate is more difficult to handle in other ways. Dissolve
pieces of the cellulose sheets in amyl acetate or butyl acetate and keep the
jars stoppered tightly to prevent evaporation. To retard setting, add 20 per
cent diacetone alcohol to one of the solvents. Acetone dissolves celluloid,
but is apt to leave a foggy film and cause weaker casts.

Paint the plastic solution on plaster molds that have been sized with
glue. Release the molds by soaking them in cold water to soften the glue.
This method of casting produces sharp detail, casts have a lifelike texture
and are pliable and strong. Walters (48), commenting on the use of plastic
in casting, draws attention to the importance of correct colour tints and degree
of translucence to give a natural appearance to the finished cast. He accom-
plishes this by adding the correct tint to the translucent medium that form
various layers applied in building up the cast.

The method has been adapted, especially at the Chatham laboratory to
reproduce deciduous foliage and, to some extent, hairless larvae. Whole onion
plants have also been cast successfully. Plastic casts obtained have proved
much superior to those made with wax both in detail and in durability.

28

Figure 26

Wax larva cast in
plaster mold.

Preparing Waste Molds of Leaves in Plaster — It is important to use plaster
giving a hard, dense surface. Probably the best Canadian plaster available
for this work is Hammer Brand Molding Plaster. In preparing leaf molds,
use fresh crisp leaves whenever possible. Lightly coat the reverse side of the
leaf with plaster and let it set. Add successive thin coats to avoid flattening
any parts of the leaf. When sufficient plaster has been applied, turn the leaf
over and lay it on a sheet of soft water clay. The plaster on the back holds
the leaf in its natural shape until the mold is made.

Build up the clay along the edges of the leaf until a complete, narrow,
flat border is formed. Pour water into a flat mixing bowl and sift in white
molding plaster until it stands dry above the water. Use enough plaster to
make the mold according to the size of the leaf, and about half as much water,
by weight, as plaster. While the water is seeping through the plaster, use
the thin portion around the edges to paint the entire leaf surface, thus avoiding
air pockets between the leaf and the plaster. Mix the plaster in the bowl
carefully without stirring in air. Pour the plaster over the leaf and on the
narrow, flat border of clay. Have the plaster sufficiently thick so that it
will not run on the surface of the mold. Large leaves such as corn or tobacco
need reinforcements of string, cheesecloth, or wire through the mold. Allow
the plaster to set. Trim the edges where necessary to form a smooth, narrow
border around the impression. Remove the leaf and let the mold dry
thoroughly.

Size the mold on the impression and the narrow border with three coats
of 20 per cent liquid glue. Stop when the first sign of gloss appears on the
dry surface. Remove any spots of gloss with a swab moistened with water or
acetic acid. Let the mold dry for one week after sizing.

Casting Leaves with Liquid Cellulose Nitrate — When casts are to be made
that will be viewed with transmitted light, any thick areas on the cast will
show darker. Before sizing the mold, speckle it with India ink to make it
easier to apply coats of even thickness; the spots will show through the first
few coats (Fig. 27, upper).

To prepare the casting medium, use Formula 45 (p. 70). When the
cellulose has dissolved completely, mix in the pigments. Use only high-grade
artists' oil colors as they come from the tube without thinner. About

29

2 per cent pigment to dry weight of cellulose makes an average mixture.
Do not add too much pigment to the medium because shrinkage in drying
intensifies the color. If the plastic lacquer is cold, warm it gradually to
70° to 75° F; then it will spread more evenly.

Make small trial casts until the desired color is attained. Remove the
cast as described later, and compare it with the natural leaf or a color
sketch. When the color in the trial cast is satisfactory, mount it on a card
together with the tints of liquid plastic used.

Practically all leaves have contrastingly colored midribs. Build these
up with a number of light coats first. This may be accomplished by using
masking tape. Lay a strip on each side of the groove and paint the liquid
right over it. Remove the masks after each coat; the drying plastic will pull
loose if you don't.

When casting the underside of a leaf with prominent midribs and veins,
make sure that the grooves in the mold do not become bridged over. If
they do, clean them out and start over because bubbles are sure to form
under this condition. Better results will be obtained in this type of casting
if you store the mold in a confined space between coats. This procedure
produces better detail in casts that have decidedly uneven surfaces. As
mentioned above, there is always danger of bubbles forming when casting a
leaf with prominent narrow veins. When this trouble is expected, after the
last coat is applied place the case on the mold in an air-tight box without
solvent to dry slowly for three weeks. This treatment reduces the chance
of bubbles forming in the cast. Partly open the box cover and leave the cast
in the box for another week, then remove and dry thoroughly.

Dry casts of small leaves with normal veins in an open room free of
drafts. Do not dry casts between coats in the sun or in currents of air.

Figure 27

Upper, plaster waste mold

speckled with ink

to aid in applying even

coats of liquid plastic.

Lower, plastic cast

on the mold.

30

Do not allow a coat of plastic to dry too much before applying another or
the cast may lift from the mold in places, leaving flat areas in the impression.

After applying the preliminary midrib coats, paint a coat of light green
plastic over the entire mold surface then alternate with several deeper shades
to give a lifelike appearance to the cast. When stickiness has disappeared
from each of these coats, mask and paint another midrib color. Continue
this until the midribs are just dense enough that the darker colors painted
on them will not show through the finished cast. Then apply the blade
colors over all finishing with a light tint.

In applying the coats, be careful not to wipe the high areas too thin.
If the join with the midrib is too sharp, stipple with solvent to soften the
effect. The period between coats varies and must be judged by the condition
of the preceding one; apply another coat when the surface is no longer
sticky. The cast must not dry too much before all the coats are completed.
Turning the molds continually on an inclined turntable causes the plastic
lacquer to lie evenly and not run into depressions, as often happens when
the mold is left flat. To keep the plastic from flowing, molds may be turned
upside down between some of the coats. When too much plastic flows into
depressions, stipple it out with the brush while applying the coat.

When it is necessary to leave an unfinished cast overnight or for a few
days, place it in an air-tight box with a little amyl acetate in an open dish
to prevent the cast from drying. Too much solvent in the dish will cause
the plastic to run. All stickiness should leave the cast before it is put in the
box because it will not dry in it.

Releasing and Cleaning the Cast — Place the thoroughly dried cast and mold
in cold water overnight. Remove the gloss from the last coat of plastic, while
the cast is on the mold, with a natural-bristle toothbrush using ground pumice
and water. The water softens the glue and allows the cast to be lifted from
the mold. Brush off bits of plaster that have pulled from the mold using a
brass brush such as is sold for cleaning suede shoes. The cast may appear
clean when wet but have white spots of plaster showing when dry. If
repeated brushings do not remove all the plaster, brush over with Formula
47 (p. 71), which makes the plaster transparent. Trim the waste plastic
around the edges of the impression.

Retouching and Shaping — Leaves coming from the molds are usually com-
plete and do not need added coloring. If retouching is needed, it is best
to use Formula 48 (p. 71).

Properly made molds of leaves should produce casts that need no
shaping. When necessary, you can reshape leaves in hot water. Then
holding the leaf in the desired shape, immerse it in cold water. When cold
the cast will retain the altered shape. Soften large leaves with steam applied
through a hose to limited areas. It may be necessary to bind casts of large
leaves to forms and steam them to shape, leaving them in position to cool.
Cloths dipped in very hot water and applied to small areas will soften them
sufficiently for shaping. Plastic casts changed in shape without using suffi-
cient heat may return to the original form.

To remove gloss from the surface of a cast leaf, dip a brush in benzene,
rub it on a cake of beeswax, and paint the glossy surface.

31

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Casting in Plastic from Rubber Molds — Walters' method of casting leaves
with liquid cellulose nitrate from rubber molds has been used with good
results. Latex takes finer details than plaster and eliminates the extra work
of removing plaster from the cast; it can be removed without a separator.
The method has its limitations, however. It is more applicable to small
leaves, because these may be fastened more securely than large ones to bases
to counteract curling caused as the plastic dries and shrinks.

To avoid flat places on the mold, pour a "pancake" of plaster on glass.
Lay the leaves in rows on the plaster but be careful not to trap air under the
leaves. Make sure that all edges are in contact with the plaster. Let the
plaster harden. Make the rubber mold in one sheet; no separator is needed.

Paint the coats of latex directly on the leaves and surrounding plaster,
making the coats uniformly thick over the entire mold. Let each coat dry
before applying the next one. While the second last coat is still tacky,
sprinkle a layer of glass fibre or absorbent cotton on the mold for reinforce-
ment; the final coat over this acts as a bond. Allow at least three days for
drying before releasing the mold.

Before casting, tack the mold all around the edge on a thick plywood
board; this avoids curling while the plastic cast is drying. Casting proceeds
in the same manner as with plaster molds (Fig. 32.).

Cold Press Casting of Leaves and Petals

This method has been practised in several museums. Clear cellulose
acetate sheet was used as the casting medium by some, but for large leaves
or petals cellulose nitrate sheet makes stronger casts.

Preparing the Molds — Hang the leaves or petals individually in a row by
running pins through the bases, exposing the undersides. Mix plaster, and
paint these surfaces with successive coats until the plaster holds the leaves
firmly in position. When the plaster has set, remove the leaves or petals.
Roll out a sheet of soft water clay. Lay the plaster mold, from which the
leaf or petal has been removed, face up on the clay. Model around the
mold to form a smooth edge on the clay. Follow this procedure through
the series. Place a dam or form around each mold to contain the plaster
that will be poured.

Apply a separator, Formula 32 (p. 68), to the plaster. Paint thin
plaster over the mold to exclude air bubbles and pour additional plaster to a
depth of 1 inch. When the plaster has set, separate the pieces.

Casting — Prepare a lump of plasticine a little larger than the mold.
Press the face of the last section of the mold poured into the plasticine
until a good impression is formed. Cut a piece of cellulose nitrate sheet,
.005 or .010 inch thick, slightly larger than the mold. Place it in a cold
bath, Formula 46 (p. 70). When the sheet is limp and rubbery, dip it in
cold water and quickly remove all water with absorbent cotton. This is
important. Any water left on the plastic will cause defects on the cast.
Place the sheet of plastic over the impression in the plasticine and press

34

Figure 32

Rubber mold for

casting leaves in

liquid plastic.

Figure 33

Cold-press casting in
plastic. Plaster mold,
plasticine, and
cast leaf.

the mold firmly into it. Lay a weight on the mold and allow it to set; time
needed is usually about fifteen minutes. Trim the waste edges. If the
cast is a petal, it is ready for coloring. With leaf casts, fasten a plastic-
coated wire on the back of the midrib base with Duco cement to form the
petiole (Fig. 33.).

To color this type of cast, use artists' tube oil colors thinned with
spirits of turpentine. If no gloss is desired, add 25 to 50 per cent carbon
tetrachloride to the turpentine. With casts having sharp details, the pattern
may be worked out with an airbrush by spraying across the cast surface,
just striking the high parts. Iridescence may be attained by laying one
color over another. Do not use vermilion or the cadmiums if translucency
is desired.

A Plastic Material for Cold Molding

Methyl methacrylate comes in liquid, granular, and sheet form. The
addition of a plasticizer such as dibutyl phthalate forms a paste that can be
molded. The resulting medium has a white, marblelike translucence. This
material is useful in building up thick midribs in plastic leaf casts.

35

Casting Foliage for Miniature Groups

Rowell (34) used type metal or stereotype plates for mold material.
He sketched the leaf pattern on the metal face and worked out details with
engraving tools. A separator was applied and the cast made in liquid
cellulose nitrate, which was released from the mold by soaking.

The Harvard College forest models in the Petersham, Mass., Forestry
Museum made by Theodore Pitman are excellent dioramas. Copper wire
was twisted together to form branches of trees, and the long ends were
bound together by wrapping wire around them to form the trunks. Needles
and leaves were made of sheet copper by photo-engraving process, soldered
to wires, and twisted into the branches. The branches were dipped in
molten solder to stiffen, and colored by hand painting and spraying.

Embedding in Plastic

This method may be used for displaying preserved biological materials.
The embedding medium is a syrup of polyester resin. The catalyst may be
one of several chemicals; Ward's catalyst for their monomer (Bio-plastic)
is tertiary-butyl-hydroperoxide. Adding the catalyst to the monomer causes
it to jell, bringing about the process of polymerization. It is later cured by
heat to give a hard, clearer-than-glass plastic in which the specimens are
embedded.

Much has been published on this method and the techniques involved
need not be discussed here. Ward's (5 1 ) gives the results of a wide range of
experiments, both of embedding in plastic and of casting from flexible
molds. Special treatments for various subjects are described. Apparently
insects were the most difficult. Fessenden (8) dealt very thoroughly with
the preserving of natural color in plant specimens mounted in plastic blocks.
The Castolite Company (6) in their instruction manual have explained the
simple method of embedding in plastic without heat and the professional
method with heat. The publication also describes the casting of solid
subjects in plastic from flexible molds. Raizenne (30) adapted the method
to display deciduous leaves.

PAINTING AND ASSEMBLING

Painting

Correct color and texture are important features of plant and insect
exhibits. The form and detail are obtained by careful casting, but faulty
finishing may ruin an exhibit. Use good artists' oil paints in the painting
process.

Painting 3 -dimensional objects is very different from painting on a
flat surface. Shadows in pictures are fixed, but insect and plant exhibits
must be colored so that the lights used to display them produce the highlights
and shadows naturally. All colored objects, when placed in display cases,
tend to appear darker; it is important to use tones that are not too dark.

36

Fresh insect or plant material from which molds are made is seldom
available by the time casts are ready for painting. It is imperative, therefore,
to make good color sketches from the subjects while they are still in a
fresh, natural condition. Make the sketches in oil paints if oils are to be
used to color the exhibit.

When it is feasible to use the airbrush it is possible to obtain more
lifelike results. This is especially true with thin leaves; transmitted light
brightens them and shows brush marks if they are hand-painted. With all
subjects, it is well to use paint sparingly. An object that looks painted
never duplicates the original.

Beeswax dissolved in benzene or xylol and lightly tinted and sprayed
on painted wax casts of fruit will give them greater depth of color. Adding
a little Damar varnish to the solvent produces a glossy effect on the cast.

Many special color textures may be obtained. For example you can
duplicate the flaky effect on the skin of new potato tubers by painting a
coat of liquid plastic on a rubber glove. When it dries, stretch the glove
and the film of plastic will crack and curl. Apply the flakes to the surface
of the potato while the paint is still tacky.

Assembling Plant Parts

Before molds can be made of a plant, it must be taken apart to prepare
molds of the individual parts. The drawings and color sketches made at
this time determine the accuracy of the final assembly. In plant sketches
give the general outline of the plants, positions of leaves, and distances
between them. A convenient method of identifying positions of leaves
on a plant sketch is to number them clockwise or counterclockwise around
the stem.

A Potato Plant — A potato plant will serve as an example. Assume that all
the wax leaflets are cast, shaped, colored, and lying in position on the original
sketches of the compound leaves. The terminal leaflets will have wires long
and strong enough to support the lateral leaflets. File flat areas on the rachis
wires for attaching the wires of the lateral leaflets; flatten all wire ends of
the leaflets parallel with the leaf blades and bend to fit the central wire
for soldering.

Solder all leaflet wires to the rachis wire, beginning with the first
pair below the topmost leaflet. Place the rachis wire in a vise. See that
the flat areas on the wires make even contact then apply soldering flux,
Formula 19 (p. 65), to the wires and solder quickly. The heated areas
of the wires must be cooled immediately or the heat will travel through
the wire and melt the wax. To cool quickly apply wet swabs of cotton
or pour a spoonful of cold water over each join.

Tint beeswax pale green and build up the rachis by applying successive
layers of hot wax with a spatula. Model the rachis making smooth con-
nections with all petioles. Model the characteristic grooves on the rachis
surface using a specially shaped scribing tool. To prepare this tool, flatten
the end of a wire and file it to make a template to conform with the pattern
on the original stalk. Scribe the rachis while the wax is warm but not too
soft.

37

Figure 34
Compound leaf.

Upper, potato leaflets
soldered to central wire.

Center, leaf stalk
modelled in wax.

Lower, stem and midribs
masked for spraying
leaf blades.

Spray the entire compound leaf with pale, greenish yellow as a ground
color. When the paint is dry, cut masking tape to fit all midribs, petioles,
and the rachis. Fit these in their exact positions before further spraying
(Fig. 34).

Spray all the leaf surfaces with the blade color, leaving the undersides
slightly lighter. It is good practice to test the density and evenness of the
spray by holding the leaf between the eye and a light. To blend colors,
remove all masks and spray the entire leaf very lightly with the last color
used. A pale green tint of paint sprayed lightly will represent the bloom
usually seen on plants. Dip a bristle brush in white cotton flocks and stipple
the freshly painted surfaces to duplicate pubescence.

Cut a piece of 12-gauge galvanized wire for the plant stalk and taper
one end for the top. File flat areas for the compound leaf attachments.
Locate the points of attachment from the drawing prepared from the original
plant stalk. Apply shellac to the wire and wind it tighly with cord, keeping
it away from the flat areas; this will act as a bond for the wax modelling.
It is easier to model wax over this wire before attaching the compound
leaves. In order not to lose the points of attachment, solder a section of a

38

common pin at the upper edge of each flattened area. Model hot wax
over the wire to the size of the original stalk.

Cut a section of wax away just below each pin marker. Beginning at
the top, solder each compound leaf in place and model over the joins with
tinted wax. Prepare the winged flanges of the stalk by using Japanese
paper dipped in pale green wax. Cut narrow strips from this, fold them
sharply lengthwise, and cut narrower strips from the folded edge. Cut
grooves in the wax with a scalpel point and insert the strips, building up
against them to restore the original shape. A final light spray finishes
the coloring.

Insect injuries and other fine hand painting should be done under a
lens. When the painting appears satisfactory through the lens, there should
be very few brush marks noticeable with the naked eve.

Branches of Trees — Green sections of tree trunks or heavy tree branches
usually crack badly near the cut ends while drying. This may be overcome
by coating the ends with melted beeswax and making a fresh cut above
the wax when the wood has dried.

When assembling exhibits of tree branches in permanent cases, it is
often difficult to attach small ones to the back of the display case. Make
special drills by grinding sewing needles of various sizes to drill points.
Use a speed drill with a foot control so that both hands will be free; fasten
the drill head to a small bench vise. Hold the branch against the drill point
to drill the holes.

Arrange the branch in the case and push a pin through each hole to
mark for drilling in the back of the case. Drill the holes with the same size
of drill as was used for the branch. Push the pins in the branch through the

Figure 35

Exhibit of insects
on a hill of potatoes.
Prepared in wax
by casting and
modelling.

(Displayed in Ento-
mology Laboratory,
Chatham, Ont.)

39

holes in the back and clinch them into the wood. The pin heads in the
branches can be hidden by paint or covered with bits of bark.

Fruit and Vegetables — Casts of small fruits and vegetables are temporarily
mounted on wooden blocks for coloring and storing. Two holes are bored
in the blocks for inserting the staple prongs.

To assemble the finished casts in a display unit, make a template of thin
cardboard to fit inside the unit. Mark the label positions on the template and
place the models on blocks in the arrangement they are to have in the finished
exhibit. Mark around each block on the template and for each item use the
following procedure.

Remove a cast from a block, cut a paper the size of the top of the block,
and mark the positions of the two holes. Lay this paper within the outline
of the block on the template and mark for the two holes. When ready to
attach the models, first fasten the labels, from measurements on the template,
with bookbinders' paste. Then lay the template in place and punch through
the pairs of hole marks into the case back to mark for drilling. Drill all
holes with a drill the size of the staple wire. In the back of the case cut
a slot between each pair of holes to receive the wires when clinched to hold
the casts. For soil profiles made over wood and mache forms, fasten with
two screws through the back of the case.

Mount photographs in exhibits by applying bookbinders' paste over all
the back surfaces of the prints to keep air from getting under the prints and
buckling them during weather changes. A photographer's rubber roller is
a useful tool for obtaining an even contact of photographs and labels in
the cases.

PRESERVING CONIFEROUS FOLIAGE

Fortunately, it is not necessary to reproduce artificially the foliage of
coniferous evergreens. A recent technique by Raizenne (29) retains the
needles on the twigs almost indefinitely. After treatment, painting will
restore the natural color.

Soft needles of spruce or balsam in the new spring growth do not
process; after curing they will shrink and curl as they dry. To overcome this
disadvantage, duplicate the new growth artificially or use older needles of the
proper size and depend on coloring to simulate the new growth.

Ethylene Glycol-Gelatin Method — Select branches of suitable size and shape
and process them as soon as possible after cutting. Pines, balsams, and other
evergreens with a high pitch content should have the surface pitch removed
before treatment. Thoroughly wash all frass, webs, and dirt from evergreens
with severe insect injury before they go into the glycol bath. Any substances
left on the needles when the branch is dipped in gelatin will be sealed in,
causing roughness over the foliage. Submerge the branches for two weeks
in the ethylene glycol solution, Formula 30 (p. 68); remove excess preserva-
tive by shaking gently. Dip several times in the gelatin solution, Formula 3 1
(p. 68), while it is still warm. Shake the foliage well after each dipping to
remove excess film between needles.

40

EUROPEAN SPRUCE SAWFLY

Gilpiniae hercyniac (Htg.)

HEALTHY LARVAE FEEDING ON NEEDLES Of SPRUCE

COCOONS

SPUN UP IN GROUND FEMALES

LARVAE DEAD AND DYING FROM VIRUS DISEASE

ADULTS
FEMALE LAYS ABOUT 45 EGGS

LARVA
INSIDE

- i

ADULT
INSIDE

-

ADULT
EMERGED

«» 1

EATEN BY

SHREW

VERY RARE AND DOES NOT

FUNCTION : FEMALE PRODUCES

YOUNG FEMALES WITHOUT MATING

LAYING EGG IN SLIT MADE IN NEEDLE
WITH SAW-LIKE OVIPOSITOR

Figure 36 — Exhibit of the European spruce sawfly. Preserved foliage,
colored. (Displayed in Forest Biology Laboratory, Fredericton, New

Brunswick.)

With evergreens having closely set needles, it is necessary to separate
the needles after each dipping so that they will not stick together. When two
needles dry in contact, you will tear the gelatin coat when separating them.

Allow a few days to dry and then color the needles with oil paints to
match the prepared color chart. Use thin oil paint and with a fine sable
brush paint each needle individually. Starting at the base of the needle make
each stroke continuous to the tip. The bloom effect may be obtained by
spraying with a pale paint mix.

If the needles are not firmly attached after processing, it is the result
of one of two things: either the branches were not treated in the glycol bath
soon enough after cutting or not enough gelatin was deposited over the
needles.

41

54899-0—4

Mr. Emil Sella, Natural History Museum, Chicago, processes his ever-
greens with glycerine and restores the color with an airbrush, removing
color on the branches with a brush and turpentine. This method of color-
ing may be used for group work, however hand painting of small sections to
be viewed closely will produce finer results.

Glycerin-Shellac Method — Other methods of preserving evergreens are avail-
able. Mr. D. M. Blakely (in litt.), Cranbrook Museum, Bloomfield Hills,
Mich., using an acetone-alcohol and glycerin-formaldehyde method, pro-
cessed a black spruce tree in a habitat group which was very successfully
mounted in a museum, but was too fragile to ship.

Processing Larch Branches — The glycol method does not work well on larch.
The leaves are held firmly in the fascicles, but they curl and shrink. Select
branches with mature leaves. Place them in glycol solution and agitate the
individual branches until the leaves separate in the fascicles. Leave them
in a natural position for two and a half weeks.

Remove the branches from the preservative, shake each well, and dip in
warm gelatin solution while still wet. Remove the excess gelatin by
striking each branch gently on paper. Dip one branch at a time and shape it
before the gelatin dries and seals the needles together.

Use an air hose with a pressure of about 25 pounds with a circular
motion on each fascicle until the needles stand free from one another. Separate
needles that stick together. When the gelatin solution has become cooler
and the branch partly dry, dip it again taking care not to melt the first coat.
Repeat the air nose treatment and pin in position on a sheet of soft plywood,
cork, or corrugated paper. Separate any needles in contact and allow the
whole to dry thoroughly. After the branches have dried, spray them with
gelatin twice more to strengthen the fascicles.

More natural foliage may be made artificially from thin sheets of plastic
cast in color. Cut needles individually, assemble them in fascicles and fasten
to the branches with "Duco" cement.

BUILDING ENLARGED MODELS

For exhibiting certain insects, it may be necessary to prepare enlarged
models. These appear as seen through a microscope with all external parts
highly magnified. This is the only graphic method for exhibiting small insects
other than using enlarged drawings or photographs. Make models from
suitable materials such as plastic, plaster, wax, wood, or metal; in each case
the medium or media chosen must be suitable to portray the several parts of
the insect.

The detailed procedure that follows is an example; it was used to
prepare an exhibit of the wheat stem sawfly for the Empire Exhibition in
London, England, in 1949 (Fig. 37.).

An Exhibit of Wheat Stem Sawfly — To avoid making molds and casts for the
enlarged stems of wheat, a medium of the correct size, I inch in diameter,
was found in tubes and solid rods of cellulose butyrate. On these it was

42

HOW THE WHEAT STEM SAWFLY HARMS THE CROP

HOW SCIENCE RESCUED THE FARMER'S CROPS

Figure 37

Exhibit of the wheat

stem sawfly.

Models enlarged six

times. Made of

cellulose butyrate.

(Displayed at

Permanent Canadian

Exhibition,

London, Eng. for some

time after 1949.)

possible to model furrows imitating those on a wheat stem. These furrows
were longitudinal in groups of two to four fine ones alternating with a deeper
one; a short length of the material was used for a trial modelling of the
surface texture.

The Stems — You use six tubes and two solid rods of cellulose butyrate for
modelling the six wheat stems that appear in the exhibit. Cut the tubes and
rods to the desired lengths and leave \ inch to spare on each one for later
trimming. This practice will also allow cutting of the striae — which is
described later — to reach the ends.

To form a node, the swollen joint on a stem, cut two sections from
a spare piece of tubing; make one piece H inches long and the other 1£
inches long. Split each down the side and place them in hot water to soften.
Apply "Duco" cement around the tube where the node is to appear and
place the longer section from the hot water around the tube on the "Duco"
cement. Fill in the gap caused by spreading of the section with a piece of
the same material. Repeat with the shorter section, placing it over the first.
When the adhesive has hardened, grind to the shape of the original node.

Model the striae, the fine longitudinal grooves on the stem, directly on
the plastic stems. A standard 10-inch file has striae properly spaced to
represent the pattern on a wheat stem enlarged six times. To make a holder,
or sled, for the cutting tool and a base to guide it, proceed as follows:

Nail two boards 2 by 20 by T% inches to a base board 4| by 20 by
f inches, leaving a slot in the center into which the butyrate tube fits snugly.
Gouge a hollow in the base where the node will rest. To make the sled,
which will hold the cutting tool, fasten a piece of wood 3 by 5 i by f inches
with glue and screws on the edges of two blocks, each If by 3 by I inches.
Fasten a 10-inch file horizontally on the end of the sled with four small
screws. The bottom edge of the file should lie about i inch from the
bottom of the sled runners which rest on the outside edges of the baseboard.

43

54899-0—4*

Screw a stopper on the end of the base to hold the plastic tube from slipping
endwise. Fasten the base on the bench, pointing away from you.

With the plastic tube in the slot, grasp the sled with the file on the side
next to you, and tipped so that the corner rests against the plastic. With a
firm, continuous stroke, pull the file the full length of the stem. Turn the
plastic tube after each stroke so that all the spaces between the striae are equal.

Figure 38 — Tool for scribing striae on enlarged plastic models of wheat

stems.

Now cut the deeper, longitudinal furrows, mentioned above. With a
fine-pointed scalpel, cut a groove in the plastic tube where it rests in the
slot; use the wood against which it rests for a guide. Turn the tube after
each groove is cut and continue around the tube. Make these grooves about
i inch apart, but vary the spacing slightly.

With the striae now completed, cut the stem ends to shape and slice out
sections of the stem to expose the interior as illustrated in Fig. 37. Using
a ^-inch steel bit in a speed drill, model the texture of exposed interiors
and the cut ends. With the bit held vertically, draw it over the surface of
the area being shaped. If the drill is held lightly, its slight bounding motion
will form small pits in the plastic which will then resemble the natural texture.
Heat the modelled stems in hot water and bend them to the desired shapes;
holding them in correct position, dip them in cold water until they set.

The Leaves — Cut a leaf section from a wheat stem, and separate the blade
from the sheath. Flatten them under a sheet of glass. Draw enlarged
patterns from them (Fig. 39A). Fasten a sheet of cellulose acetate 0.002
inch thick over the patterns and, with a sharp-pointed tool, scribe the outlines
and all striae appearing on the pattern. Cut out the two sections and sand-
paper both sides of each lengthwise to make the proper texture. Bind the
sections in position temporarily around a piece of f-inch rod of butyrate.
Place the leaf and rod in hot water until they are well heated and then dip
them in cold water while they are still bound on the rod. Remove them,
lap the edges slightly, and fasten the sheath with ligule to the blade with

44

"Duco" cement. Joining these two pieces, one with a straight edge and the
other with a concave edge, causes the leaf blade to stand out from the stem
as in nature (Fig. 39B.).

The Stubble — The surfaces of pieces of tubing used to represent stubble have
no striae; they are just sandpapered lengthwise to remove gloss. Cut triangular
sections out of the bases of tubes used for stubble so that the remaining
points, when pressed together, will form rounded ends. Heat the bases in
hot water and bend the points until all the cut edges join. Fill any gaps with
butyrate chips softened in a flame.

To form roots for the stubbles, rip pieces from a plastic rod to the
approximate sizes of the roots required. Dip them in acetone and scrape
to shape. Attach the roots to the stems by boring holes to fit the root bases
and insert the roots. Build up around the root bases with thick liquid
butyrate. Model all cut edges and exposed interiors of the stubbles as
described for stems.

Sheaths on dry stubble are usually badly worn by wind; this condition
must be simulated in the enlarged sheaths. Make them from a 0.005-inch
sheet of cellulose nitrate that has been scribed for striae and painted with
brownish yellow acetone. This colors and withers them in one operation.
Cut out the sheaths then shape and fit them as previously described.

Coloring the Stems, Leaves, and Stubble — Coloring of the models is very
important. This is best accomplished by spraying, using masks to cover parts
not to be colored in the first spraying. Cut pieces of masking tape to fit all
cross sections of stem ends, openings made to expose interiors, and the light
areas at the bases of the leaves. This way you expose only the exteriors of
the stems and the portions of the leaves and sheaths to be colored green.

For coloring enlarged stems and leaves in plastic when color has not
been incorporated into the medium, best results are obtained by applying
the color with an airbrush. Lay one tint over another to give a more lifelike
appearance. Mix three tints from tube oil colors — a pale green for the first
coat, the full blade or stem color next, and last a bluish white — the last
represents the bloom, a light powdery-appearing effect found on many plants.
To thin the paint, use Formula 43 (p. 70). Hold the airbrush well away
from the object and at right angles to it. Apply the various coats one after
the other without waiting for the previous coat to dry. When the paint is
dry, remove all masks and spray the exposed interiors lightly with sap green
and white tint.

Spray the stubble white, and then yellowish brown, made by properly
blending yellow ochre, zinc white, and raw umber. The bases of all stems
and stubble that will be covered by sheaths may be left uncolored.

The Female Adult Sawfly — This model was made mainly by modelling with
liquid plastic over a plaster core and using wire reinforcements for the
antennae and legs. The construction proceeded as follows:

Model the head, thorax, and abdomen in one piece from white beeswax,
working directly from the microscope or an enlarged drawing. Make a
2-piece plaster mold from this model and from the mold cast the body of the
enlarged model in plaster. Run a 16-gauge wire through the center of the
cast from the head through the ovipositor. Leave a length of wire with

45

which to mount the model. When the plaster cast is dry, paint it with black
cellulose nitrate until no white plaster shows. Paint the color pattern on
the black plastic with yellow liquid plastic.

Cut monel wires for antennae from 0.018-inch wire and for legs from
0.022-inch wire. Coat the wires with tinted liquid cellulose nitrate thick
enough to model antennae and legs. For the spines near the joints of the
legs, use sections of entomological pins. Drill holes in the head and thorax
to receive the antennae and legs.

Mount the natural wings on a microscopic slide and project them to
the correct magnification on a card. Trace the wing margins and the venation
pattern. Fasten a piece of cellulose nitrate, 0.005-inch thick, over the wing
outlines and trace them with a sharp-pointed tool. Cut out the four wings
and paint the grooved sides with black India ink. Before the ink dries, wipe
the plastic, leaving ink in the grooves only. Mix oil paint to match the wing
tint, add a drop of essence of pearl to give slight iridescence, and spray
lightly on both sides of the wings. Attach the wings to the thorax with
"Duco" cement. Mount the model on the stem by boring a hole through
it to carry the wire protruding from the ovipositor. Adjust the antennae
and legs and fasten them in the holes prepared in advance (Fig. 40.).

The Larva — Model the larva in wax from microscopic examination or
enlarged drawings. From the wax model make a 2-piece plaster mold, and
from the mold cast in wax the several larvae needed. Secure proper-sized
spines from cactus leaves or a similar source and insert them in the casts
for setae.

Assembling the Parts — To attach a leaf to the stem, apply "Duco" cement to
the inside of the sheath and bind it in place on the stem with a cord. Let it
dry thoroughly. To fasten a wax cast of a larva in the stem or stubble,
embed entomological pin points in the stem at the point of attachment, place
a piece of cotton saturated with "Duco" cement between the pins, and press
the larva firmly into position. Distribute frass made of tinted plastic sawdust
around the larvae. For the plug in the end of the stubble section, showing
the position of the overwintering larva, use cork covered with brown-tinted
plastic sawdust.

Figure 39

Left, enlarged

pattern

of section of

wheat leaf.

Figure 40

Model of the

wheat stem

sawfly in

plastic.

46

To fasten the exhibit in the case, make two rectangular staples for each
stem, the middle section of the staple is 1 inch across. Cut two grooves in
the underside of the stem deep enough to anchor the staples, with the middle
cross section in the holes. Fill the grooves over the staples with liquid cellu-
lose butyrate. The two prongs of each staple go through the back of the
case. The base of this exhibit measured 20 by 27 inches.

Animated Models

Construction of enlarged models opens a large field for mechanically
minded operators, especially for making animated models. Carmel (5), of
the Cranbrook Museum, Bloomfield Hills, Mich., constructed three animated
fireflies, enlarged 17 times. By means of a synchronous motor and a series
of cams operating microswitches, the abdomens of the fireflies were illumi-
nated in proper sequence of timing. Balsa wood, plastic, and metal were
used. He also made a model of a blue-bottle fly, enlarged 46 times, that
showed the halteres in motion while the case lights were on.

Uses of Glass in Model Making — Von Fuehrer (47) used blown glass to make
insect models; legs and antennae were strung in segments on wire. Glass
takes paint and plastic coating satisfactorily.

AIRBRUSH TECHNIQUE

An airbrush is almost indispensable for preparing exhibits. Wax and
celluloid leaves painted with a standard brush appear uneven and blotched
when viewed by transmitted light. With the airbrush, it is possible to apply
successive light timings to ensure even coverage and proper color tones.
It is ideal for applying the ground color on wax fruit but not altogether
satisfactory for spraying preserved evergreen foliage because it is not feasible
to mask the branches. Painting the branches the same as the needles with
the airbrush, will result in some loss of natural tints from the bark when
the paint is removed.

Types and Performances — Wold, Paasche, and Thayer and Chandler are
three popular makers of airbrushes (Fig. 62, p. 74); these brushes have been
used in museums, some preferring one and some another. With the Paasche
ABG and the Wold BBF brushes, you can use thicker oil paint which is an
advantage when producing special finishes with talc, soil, or flocks on freshly
painted surfaces. Small airbrushes made to use water colors may prove
difficult to use when applying oil paints. Low surface tension in oil paint
allows the paint to run through the paint slot and hang on the tip of the cup.
If the paint is too thin it will be blown off and spatters the work; if it is too
thick, the paint slot is not kept full and the spray stops. Only experience will
show the operator how to mix oil paint suitably for use in airbrushes.

If you use oil paints, buy the best artists' paints and thin when needed
with Formula 42 or 43 (p. 70). Strain the oil paint used in airbrushes but
use paint as it comes if mixed thick for special uses, as mentioned above;
spatulate it on a palette and when the paint runs sluggishly from the spatula,
it is in proper condition for spraying.

47

Before attaching the airbrush to the hose, blow
the hose out well to remove any dirt or moisture.
Check the needle point to see that it is in perfect
condition. Never leave an airbrush for more than a
few minutes before cleaning. Flush it with turpentine
or carbon tetrachloride until all paint residue is
removed.

Air Supply — A constant air supply adjustable from
25 to 30 pounds pressure is desirable. An electric
compressor unit with capacity in this range will give
the most satisfactory results. Open the drainage valve
periodically to blow out accumulated water and dirt
from the tank. Check the oil level in the crankcase
and oil the motor bearings at regular intervals. When
a compressor unit is not available, a cylinder of
compressed, liquid, carbonic acid gas may be used.
With most cylinders, it is necessary to have a reducing
valve to control the working pressure. When reducing
pressure, it is important to reduce the pressure at
the cylinder first. For detailed instructions in air-
brush technique, consult Kadel (15) or Tobias (40).

Figure 41 —

Gauge for liquid

carbonic gas

outfit.

BUILDING INSECT DIORAMAS

More and more museums are using dioramas to portray subjects in their
natural habitats. These exhibits produce the illusion of a view through a
picture window. Up to now, dioramic exhibits have mainly portrayed large
species of animal life; little has been done to adapt the method to exhibit
insects. An insect group must necessarily be small so that the habitat does
not dominate the exhibit. By carefully choosing subjects successful groups
may be prepared. The method would be useful for portraying severe out-
breaks by insects such the armyworm and the Japanese beetle.

General Principles — In such a group the foreground, consisting of actual
insects or reproductions of them and the injury they do to plants, blends with
a curved, painted background suggesting the area of infestation. To be
successful the groups must depend entirely upon illumination from within
the case; it should be stronger than room light to prevent reflections.

It is impossible to give any illusion of distance in too small a case. No
attempt should be made to build an insect diorama with a depth of less
than 42 inches. For correct perspective the ratio of depth to width should
be 6 to 10. Place the horizon line at eye level at a height of about five feet.
The glass front should be smaller than the background to hide the ends and
top of the painting and also to avoid distortion of the background. The
glass should slope slightly outward at the top to eliminate reflections.

48

Base and Foreground — The base should slope slightly upward toward the
back so that it will more readily blend into the background.

Prepare soil surfaces as follows. Build a wooden form, cover it with
galvanized wire screen, and model the soil contours with mache (any one of
Formulae 38 to 41, pp. 69 to 70). Sterilize the natural soil to kill insects or
bacteria that may be present. Sprinkle the soil with 5 per cent glue water
and mix thoroughly until it is slightly moist but will still crumble. Apply a
liberal coat of liquid glue to part of the base and sprinkle the moistened soil
evenly over the glue; press firmly and add more soil until no glue shows
through. Continue until the entire base is covered, and then sprinkle lightly
with soil. When it is thoroughly dry, remove soil that is not attached. Some-
times it is necessary to glue on a second coat of soil to form a perfect coverage.
To make cracks in the soil use an excess of water in the soil before fastening
it to the base. Duplicate the moisture line on soil profiles by spraying with
paint thinned with boiled oil and turpentine.

Choose subject matter for the foreground and arrange it so that it will
blend into the background with no break. A photograph of the completed
exhibit should appear as a single unit, showing no break between foreground
and background.

Background — Use a sheet of galvanized iron in constructing a small group.
Nail it to a wooden frame of the correct contour; the metal should form an
even sweep all the way from near the front toward the center back with no
undulations. Nowhere on the background should there be flat areas, yet the
curve should not be part of a circle. If the sides and the center back are
not curved and are connected by curved areas close to the corners, distortion
will occur on the sides and the back; in fact, the center will appear to bulge.
Use long curves as indicated in Fig. 42.

Clean the metal surface with vinegar and water, and then apply three
coats of flat, pale blue paint. On this, sketch the scene and paint it with
oil colours. To obtain true tones, paint the background under the type of
lights to be used in the finished exhibit. Objects should be less than life-size,
even where they occur near the foreground. If the background should appear
too cold when finished, spray lightly with rose madder.

View Window — To achieve greater illusion of distance and perspective, limit
the size of the front glass. Cut off from view the edges of the sides and the
top of the background so that nothing extraneous obstructs the line of vision.
Use an apron, as indicated in Fig. 42 right, inside at the top of the glass
to further restrict the line of vision at the ceiling.

Figure 42
Plan of diorama unit.

Left, proportions
of the base.

Right, end elevation.

49

Lighting — Arrange the lights so that no shadows are cast on the background.
Accomplish this by using a wide area for light sources and having the lights
shine through ground glass. It is better to place the lights in a separate,
ventilated unit; fluorescent lights will reduce heat.

Leaves from Paper — When large numbers of leaves are needed it is best to
use metal molds but paper-based leaves may be used in dioramas that have
sufficient depth. Use cream, double-faced, crepe paper sized with thin, liquid
cellulose nitrate, Formula 45 (p. 70). Cut leaf blades from original patterns,
lay them on blotting paper, and form the veins with a veining tool, copying
the pattern of the natural leaves. With an embossing tool, rub between the
veins to shape these areas. To make this tool, solder ball bearings of two
sizes on a metal rod, one on each end. Wind string on the center of the rod
and lacquer it for a handle (Fig. 43.).

Figure 43
Tools for
modelling paper-
based leaves.
Upper, veining tool.
Lower, embossing
tool.

Attach tapered wire coated with liquid plastic to the back of the midrib,
and then shape the blade as desired. Dip in hot, colored wax and twirl
rapidly by the wire to remove excess wax. To keep the wax from spattering,
tie a paper collar around the top of the pot. Almost any type of leaf may
be made by this method.

Although not dioramas, two 8-foot groups were made illustrating damage
and control of the pale western cutworm and the clear-winged grasshopper
on wheat for the World's Grain Show at Regina, Sask., in 1933. These were
constructed in cellulose nitrate, one of which is illustrated in Figs. 44 and 45.

DISPLAY UNITS AND LABELS

Display completed exhibits in closed units to protect them from dust,
breakage, and insect attack. Also, the exhibit must be securely fastened for
shipment. It is necessary, therefore, to provide a case that is attractive in
design, that has a glass front; there must be a dustproof base or a back on
which to fasten the exhibit.

Display Units

Display units may be of various designs and sizes to suit the exhibits.
Most exhibits made at the Chatham laboratory were mounted in standard
units of two sizes, 16 by 19 by 3i inches and 18 by 21 by 3i inches. They

50

Figure 44 — Injury by the clear-winged grasshopper to Marquis wheat,
and egg bed in sod. Plants in cellulose nitrate. (Displayed in National

Museum of Canada, Ottawa.)

Figure 45 — Grasshoppers emerging from sod, and control in wheat with
poisoned bait. Plants in cellulose nitrate. (Displayed in National Museum

of Canada, Ottawa.)

51

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are made of solid walnut with bass wood-ply wood backs and glass fronts. A
pine interliner, covering the joints on the ends and sides inside made by the
glass front, makes the case practically dustproof. Interiors are painted with
three coats of flat white enamel to which you add enough permanent blue
to give a very pale, blue-white finish. It is difficult to obtain a white enamel
that will not turn yellow in an air-tight case. It helps to leave the fronts of
the cases partly open for a week or two to dry the enamel thoroughly. This
allows a scarcely visible film of dust to form on the white paint. Remove
all dirt before attaching labels; if attached with bookbinders' paste they will
curl while drying if the surface is not clean.

Nicholls (24) recommends the following finish for the outside of walnut
cases. Brush on one coat of walnut paste wood filler; before this dries, rub
off the excess across the grain with a coarse cloth. After the filler has dried
for 24 hours, brush on one coat of Hippo oil. After another 24 hours, sand
lightly with 4-zero or 6-zero sandpaper. Apply a second coat of Hippo oil
and let it dry for 24 hours. Rub the final coat smooth with fine steel wool
and apply a coat of hard wax (Fig. 46).

Large display units for full-size plants may be patterned after those
in use at the Royal Ontario Museum of Zoology and Palaeontology, Toronto.
The display part of the unit is 30 inches each way with glass on three sides
and top. The back is of plywood, covered inside with unbleached linen.
It is mounted on a base 36 inches high (Fig. 47, p. 54).

A small glass unit for displaying a single fruit or vegetable would
consist of five pieces of plate glass, four of which are slotted into a wooden
base and the fifth piece forming the top. A case for a large potato requires
two pieces of plate glass 3i by 8 inches, two pieces 31 by 7i inches, and
one piece 8 by 8 inches. All exposed edges are smooth-polished; all the
edges to be cemented are rough-ground.

For the wooden base, use one piece of solid wood 10 inches square
by I inch thick with shaped edges. Four binder posts, A by 4 inches,
and felt washers for the posts are needed. Bore i-inch holes near the corners
of the 8- by 8-inch glass top so that they will come just inside the glass
sides. Bore similar holes through the wooden base to match these. Enlarge
these holes in the bottom of the base to accommodate the lock screws. Rout
out a i-inch slot all around the wooden base to fit the four sides of the
glass case. Cement felt washers under the heads of the binder posts,
and around them where they go through the glass (Fig. 48, p. 55).

To assemble the side pieces of glass, make a 3-sided form on a square
of |-inch plywood. Cut and grind the glass accurately. Clean the edges
to be cemented with amyl acetate. Apply two coats of "Duco" cement to
each surface of glass that will come in contact. Wedge three of the glass
pieces against the form to hold them square while drying. It is easier to
handle the fourth piece separately. Hold it in place with a wooden block
clamped to the form. When the cement on the sides has hardened, cement
the top in place (Fig. 49. p. 55).

53

Figure 47

Museum display unit.

Mount the subject on the wooden base, using the staple that is anchored
in the wax cast. Place a little latex on the bottom edges of the assembled
glass and insert in slots. Run the four binder posts through the holes and
secure the lock nuts in place.

Labels

Labels, bearing captions, are necessary in displays. The choice of
labels may add much to the attractiveness and value of exhibits. White
paper turns yellow in time. Labels prepared photographically and having
white lettering on a black background are most satisfactory. This type
of label needs no border and may be trimmed with a paper trimmer or a
razor blade. A razor blade makes a cleaner edge, especially if a sheet
of glass is placed beneath during the cutting.

Labels for exhibits prepared at the Chatham laboratory were made
at the Bio-Graphic Unit, Science Service, Ottawa. Parker (25) contributed
the following on the method. Labels are prepared entirely by mechanical

54

Figure 48 — Special display unit for a small exhibit.

Figure 49 — Method of assembling plate glass in unit shown in Fig. 48.

55

means with either the Coxhead-Liner machine (Ralph C. Coxhead Corpora-
tion, 720 Frelinghurpen Ave., Newark 5, N.J.), or typeset, depending on
the number of words in the caption and size of letters required. Further
photographic processing produces a set of captions suitable for use in
exhibits.

First prepare a layout indicating the number of captions, wording, type
font required, and relative positions. If possible, remove from the layout
all main captions calling for larger type which are to be prepared from
Coxhead-Liner type, if this is not possible, prepare a separate list. Typeset
remaining captions which contain a large amount of text and call for
smaller type.

Coxhead-Liner Composition — The Coxhead-Liner (Fig. 50), a comparatively
recent development, prepares proofs of type in a wide variety of styles and
sizes. Its main components are a chamber containing photographic paper,
developing and fixing tanks, an exposure aperture, a spacing dial, and a large
plastic disk marked with the letters and numbers of one style and size of type
around its outer edge (Fig. 51).

In operation, a selector knob brings each letter or number into position
for exposure on the 35-mm. paper tape. When you depress the exposure key,
the paper automatically advances a preset letter-spacing distance. Exposures
are made and the paper tape rolls through almost as quickly as the operator
can select letters. A line-length dial controls the length of line within a
variable setting.

The paper tape passes through the processing tanks and emerges from
the machine producing continuous line of lettering. The letters are ideal
for reproduction; they can be enlarged up to 15 diameters without fuzziness
or distortion. More than 50 styles and sizes of type are available, you
simply change the master disk in the machine to use them.

Eighteen-point Gothic copperplate is used to prepare main captions,
which are enlarged photographically to 36-point; sub-captions usually remain
in 18-point. When short sub-captions are prepared by the Coxhead-Liner
method, the 18-point Gothic copperplate is reduced photographically to
14-point (Fig. 52.). Set all scientific names appearing in main captions in
30-point Lydian cursive, later reduced to 24-point (Fig. 53.).

A 3 -line main caption containing a scientific name in the second line is
set in 18-point for the first line, 30-point for the second, and 18-point for
the third; these will appear on the exhibit label as 36-point, 24-point, and
18-point, respectively. The Coxhead-Liner provides Gothic copperplate in
14- and 18-point, and Lydian cursive in 30-point only; larger or smaller
letters of each of these styles must be obtained photographically.

Typesetting — Subcaptions, each comprising a large number of lines, are set
in 14-point Gothic copperplate and will appear in this size in the exhibits.
When subcaptions prepared by this method contain scientific names, under-
line each name (Fig. 54.).

Prepare enough copy to fill a galley, make proofs and proofread. Make
necessary corrections and pull final proofs on reproduction paper with a
suitable surface for further photographic processing.

56

EDL

EDL

12 POINT

14 POINT

18 POINT

36 POINT

Abies

Abies

30 POINT

24 POINT

HIS SMALL INSECT
:UROPE ABOUT I9(
ABIES BALSAMEA( ^
THE BARK AND SH< (§4)

BALSAM WOOLLY APHID

Adelgcs piceac (Ratz.

ON BALSAM FIR

THIS SMALL INSECT WAS ACCIDENTALLY INTRODUCED INTO CANADA

FROM EUROPE ABOUT 1900 AND HAS KILLED LARGE QUANTITIES OF BALSAM

FIR ABIES BALSA MEA (L.) MILL.. IN THE MARITIME PROVINCES. IT FEEDS

ON THE BARK AND SHOOTS BY INSERTING A LONG SLENDER TUBE BETWEEN

THE CELLS. A SALIVA IS INJECTED WHICH CAUSES ABNORMAL GROWTH

OF TWIGS (GOUT DISEASE) AND FORMATION OF A HARD. BRITTLE

TYPE OF WOOD (REDWOOD).

BALSAM WOOLLY APHID

Adelgcs piceac (Ratz.)
ON BALSAM FIR

THIS SMALL INSECT WAS ACCIDENTALLY INTRODUCED INTO CANADA

FROM EUROPE ABOUT 1900 AND HAS KILLED LARGE QUANTITIES OF BALSAM

FIR ABIES BALSA MEA (L.) MILL.. IN THE MARITIME PROVINCES. IT FEEDS

ON THE BARK AND SHOOTS BY INSERTING A LONG SLENDER TUBE BETWEEN

THE CELLS. A SALIVA IS INJECTED WHICH CAUSES ABNORMAL GROWTH

OF TWIGS (GOUT DISEASE) AND FORMATION OF A HARD, BRITTLE

TYPE OF WOOD (REDWOOD).

Figure 50 — The Coxhead-Liner photo-lettering machine.

Figure 51 — The Coxhead-Liner Typemaster.

Figure 52 — Gothic copperplate in the various sixes used.

Figure 53 — Lydian cursive, actual sixe and reduced.

Figure 54 — Proof of monotype, actual sixe.

Figure 55 — Completed caption ready for photocopying.

Figure 56 — Completed caption as used in exhibits.

54899-0—5

57

Preliminary Photocopying — Photograph the Coxhead-Liner single-line strips,
enlarging or reducing on the negatives as needed. Prepare prints from these
negatives for the artist's use.

Artwork — The layout, which was cut apart to facilitate preparation by the
two methods, is temporarily re-assembled. The contact prints from the
Coxhead-Liner strips and the typeset proofs are now trimmed and mounted
for photocopying; each caption is set up as a separate unit. At this stage,
all letters are black on a white background (Fig. 55.).

Final Photocopying — Place the completed captions layouts in position on the
copy board of the camera. Arrange to use as much of the film area as
possible and make negatives.

Direct Positive Prints — Direct positive prints can be made directly from the
negatives; the image is transposed to white letters on a black background
during processing. Direct positive paper is light in weight and it is usually
necessary to mount the print on a cardboard base for use in the exhibit.

Contact Prints — To make contact prints, the image must be transposed before
the prints are made. Expose the final negative on a second piece of film,
which results in a positive with opaque letters on a clear background. Contact
prints prepared from this positive reverses the letters to white on black.
Captions produced in white letters on a black background (Fig. 56.) give
greater contrast and legibility.

Figure 57 — Shipping cases with buffers of foam-rubber.

58

SHIPPING

Living Insects — One of the greatest difficulties in shipping living insects is
to keep food plants fresh in transit. It is safe to ship larvae feeding on coni-
ferous foliage in breeding cages (Fig. 1, p. 7). Fill the water container
with absorbent cotton before adding water, to avoid leakage. Tie the
chimney, wrap each cage in newspaper and pack in excelsior or shredded
or crumpled paper. You can ship a few small larvae in large test tubes,
supplied with evergreen twigs; wrap the cut ends in wet cotton. The tubes
should be stoppered with plugs of wet absorbent cotton.

Dead Insects — Use a wooden box with a deep, firm pinning medium securely
fastened in the bottom. With pinning forceps, pin the specimens into the
box. Place a sheet of cardboard over the pin heads, and then pack cellu-
cotton above it to hold the cardboard against the pins. Wrap the box in
paper to keep dust out, then in cotton, and pack it in excelsior in a carton
labelled "Fragile".

Evergreen Foliage — If no preservative is at hand, ship coniferous foliage fresh
from the tree, packing it as described for deciduous foliage below. However,
evergreen foliage should be partially preserved as soon as it is cut from the
tree. Place it in Formula 30 (p. 68) for one week and then wrap it while
it is still wet in cheesecloth saturated with the same solution. Wrap in plastic
sheeting and pack in moist moss. Be careful not to crush the needles and
keep the branches in their natural shapes.

Deciduous Foliage — Ship deciduous foliage fresh from the tree. Wrap the
cut end in wet absorbent cotton or cheesecloth. Wrap the entire branch in
wet cheesecloth, cover this with damp paper, and enclose the whole in a
plastic wrapper. Pack the parcel in wet moss in a carton. If the branch
must be kept for some time before shipping, before the leaves wilt place the
branch in 5 per cent formaldehyde. Never put deciduous foliage in
Formula 30.

Fruit and Vegetables — Choose specimens that have no injuries to the skin
other than the damage to be shown. Wrap each item individually in wax
paper and pack in excelsior in a wooden box.

Completed Exhibits — Glass-topped cases containing exhibits should always
have adequate packing material on all sides between them and the wooden
shipping box. An excellent shipping box for glass-topped cases was designed
by Mr. C. F. Nicholls, Entomology Laboratory, Belleville. It is made of
i-inch fir plywood with sheets of 1-inch foam rubber surrounding each case.
Thin wallboard dividers between the cases keep the weight of one case from
resting on another.

59

54899-0— 5A

FORMULAE

The formulae for preserving insect and plant specimens are listed
together here to avoid repetition in the various sections of the manual. They
are referred to in the text by formula number and page. Numbers in brackets
relate to References (see p. 80).

Preserving Larvae Dry

1. Barber's Method (28) — Kill in 80 per cent alcohol to which benzol, carbon
bisulphide, or some other fat solvent has been added at 1 part of solvent
to 10 parts of alcohol. Allow average specimens to remain in this solution
at least 24 hours; larger insects and those with softer bodies should remain
72 hours.

Change to 95 per cent alcohol and leave for 24 to 72 hours.

Dehydrate in absolute alcohol containing a piece of limestone to take
up moisture.

Transfer to xylol and dry on plaster blocks. Puncture large specimens
to facilitate dehydration.

Shrinkage may be reduced by placing the specimens in cold water over
slow heat and bringing it to the boiling point. Remove the specimens from
the heat and allow to cool to room temperature.

Larvae preserved by this method may be mounted on pins.

2. Preserving Small Soft-bodied Insects (12) — The following solution is
suitable for either soft-bodied larvae or adults:

Ethyl alcohol 85 cc.

Formaldehyde (10 per cent) 15 cc.

Glycerin 5 cc.

Place living or newly killed specimens directly into the solution and
leave as long as desired but at least 24 hours. Specimens that will later be
boiled in caustic should not be placed in this solution because it contains
formalin.

When pinned specimens are wanted, dehydrate by placing them suc-
cessively in 85 per cent, 95 per cent, and absolute alcohols, then in xylol,
leaving them 10 minutes in each.

Specimens need not be removed from the vials to make changes to
different solutions. Drain off the liquid with a small-tipped pipette. While
the specimens are in xylol, position them if they are adults on folded strips
of filter paper; place the wings in contact with the paper. Remove specimens
and paper gently and allow to dry.

3. Alternate Method for Preserving (28) — This method preserves larvae so
that they may be pinned or used out of preserving liquid. The color is lost
but may be partially restored by using Formula 4.

Pass the specimens through alcohol, 60, 70, 80, and 90 per cent, and
absolute, in turn, then through the following solutions:
2 parts absolute alcohol, 1 part xylol
1 part absolute alcohol, 1 part xylol
1 part absolute alcohol, 2 parts xylol

60

Xylol

2 parts xylol, 1 part turpentine

1 part xylol, 1 part turpentine

1 part xylol, 2 parts turpentine

Turpentine

Leave specimens in each solution for six days.

4. Staining Dry Preserved Larvae (28) — Prepare the stain with an oil paint
that is soluble in xylol. Dehydrate the specimens with Formula 3. Have
the stain rather concentrated and transfer the specimens to it. Leave them
in the stain two or three hours. Very oily specimens will not absorb stain
and must be hand-painted. Do not use water colors; the specimen will
shrink as soon as it comes in contact with water.

Preserving Larvae in Liquid

5. Craig's Solutions (origin unknown) — This solution preserves colors of
larvae very well.

Solution 1. Formaldehyde (40 per cent) 200 cc.

Potassium nitrate 15 gm.

Potassium acetate 30 gm.

Water 1000 cc.

Solution 2. Sodium chloride saturated solution

Solution 3. Potassium acetate 60 gm.

Potassium nitrate 30 gm.

Water 1000 cc.

Solution 4. Potassium acetate 100 gm.

Glycerin (chemically pure) 250 cc.

40 per cent formaldehyde 5 to 10 cc.

Water 1000 cc.

Depending on its size, the carefully washed specimen remains in
Solution 1 for one to five days. Extraction of formaldehyde and develop-
ment of gross color are usually completed in Solution 2 in one to three days.
In Solution 3, the time needed for complete development of colors in fresh
specimens is two to seven days. The specimen is placed in Solution 4 for
permanent storage.

6. Kahle's Fluid (19)

Ethyl alcohol (95 per cent) 15 parts

Formaldehyde (40 per cent) 6 parts

Glacial acetic acid 1 part

Distilled water 30 parts

Preserving Adults

7. Formalin-chloroform for Preserving Reds, Yellows, and Browns (28) —
Saturate a vial of 10 per cent formalin with an excess of chloroform. Shake
the bottle two or three times a day for a week. Pour off the saturated
solution and add the specimens.

61

8. Preserving Browns and Greens in Cicadidae and Orthoptera with Formalin

(28) — This method was used by the late W. T. Davis, Staten Island Museum.
Green preserves much better in insects soaked in formalin with about
16 to 18 parts of water for a few days than in specimens not so treated.
Place newly collected insects in formalin, pour off after a few days and
replace the cork in the bottle; this will keep the insects in a moist condition.
If the formalin is not too strong, the insects will remain pliable; it is possible
to stretch and arrange the legs as if the insects had been dead only a few days.

9. Degreasing Insects — Large-bodied moths, especially Sphingidae and
Saturniidae, often become greasy some time after mounting. To avoid spread-
ing of the grease, remove the viscera through a slit on the underside of the
abdomen. Swab out with cotton and paint the inside with arsenical soap
(Formula 11, p. 63). Fill the cavity with a twisted, tapered plug of cotton
and draw the edges of the incision together.

To degrease an old specimen, Ward's suggests the following procedure.
Pin the specimen so that the wings are tilted, and with an eye-dropper allow
carbon tetrachloride to run slowly from the base of the wing to the tip. Place
a small ball of cotton near the tip of the wing to collect the carbon tetra-
chloride, save and use again until it becomes saturated with grease (when
it turns yellow).

Peterson (27) mentions having success with a variation of Valentine's
(44) method for removing grease from larvae, nymphs, and pupae that are to
be dried. Kill the specimens in an ethyl acetate killing bottle and place
directly into ether. Several changes are necessary until no yellow shows in
the liquid; it will take two to several days. After all the fat has dissolved,
remove the specimens one at a time and place them on absorbent paper
under an electric light bulb in a gooseneck desk lamp. The heat evaporates
the ether and slightly inflates the specimen; too-rapid evaporation may burst
them. Leave under the lamp until all the ether has evaporated. If removed
too soon, the specimen will shrink. A shrunken specimen can be restored
if returned immediately under the lamp. Suspending the specimens on wire
screen in the ether should prevent the grease from penetrating the specimen.

10. Keeping Dried Specimens Free of Pests — Use mercuric chloride dissolved
in ethyl alcohol in a glass container. Thin the solution until a black feather
dipped in it will not show a white deposit. This chemical is a very dangerous
poison and must be handled with great care.

Insects not heavily covered with scales or hair may be dipped; others
should be carefully moistened with a soft brush. Place the label "Poison"
on the container and brush, and use them for nothing else. Do not mount
the treated specimen in a display unit for some time because the fumes will
turn white paint yellow.

Some German entomologists have used pure lindane in alcohol with
success; they claim it will last longer than other materials tried. It is lightly
sprayed over mounted insects and inside the cases.

Marioni (21) states that a small cellophane envelope containing 0.5 gm
of BHC mixed with geraniol, placed in a case of insect specimens and pierced
with a pin, will protect the contents from attack by insects for three years;
specimens in an unprotected case in the same room were completely destroyed
and numerous psocids, lepismids and adults of Anthrenus spp. were present.

62

11. Preserving Fresh Specimens (14, p. 346)

White bar soap, soft 2 pounds

Powdered white arsenic 2 pounds

Subcarbonate of potash (potassium bicar-
bonate) 6 ounces

Camphor 5 ounces

Alcohol 8 ounces

The soap used should be best quality laundry soap of such composition
that it can be reduced with water to any degree of thinness. Do not use
soap that becomes jelly-like when melted. Slice the soap and melt it in a
small quantity of water over a slow fire and stir occasionally to prevent
burning. When melted, add the potash and stir in the powdered arsenic.
Next add the camphor, which should be dissolved in the alcohol at the
beginning of the operation. Stir the mass thoroughly, boil it down to the
consistency of thick molasses, and pour it into an earthen or wooden jar
to cool or harden. Stir it occasionally as it cools to prevent the arsenic
from settling to the bottom. When cold, it should be like lard or butter.
To use, mix a small quantity with water until it resembles buttermilk and
apply with a common paint brush. Use this mixture to treat the body
cavities of large Orthoptera and Lepidoptera, and larvae from which the
viscera have been removed.

12. Impregnating Dried Insects — The synthetic resins "Gelva" and "Alvar"
may be used successfully to impregnate dried insects; "Alvar" is stronger
than "Gelva" but has an amber tint, "Gelva" is colorless. Dried insects or
plaster casts may be immersed in very thin solutions of either.

To dissolve, place the resin in alcohol and heat in a water bath until
it has liquified completely. Do not tighten the lid while the container is
being heated. Add more alcohol when the resin has dissolved to make a thin
solution for impregnating.

For adhesive purposes, an average solution consists of 25 per cent
resin by weight. To mend wood, saturate both sections and let dry. Apply
a second coat and let it dry. Soften the adhesive with alcohol and press
the parts together.

13. Metal Plating Insects (36) — Formula 1: To one pint of orange shellac
add i pint of wood alcohol and mix thoroughly. Attach No. 20 or other small
copper wire to the article to be plated and dip in the solution for one minute.
Remove and shake off the surplus shellac, then fill an ordinary insect powder
gun with gold bronze powder and spray, covering the shellacked surface well.

Formula 2: Especially for insects, make a thin solution of shellac by
adding wood alcohol. Place the insect on wires as in Formula 1 and spray
with this solution, using a common throat atomizer. Make a solution
by dissolving nitrate crystals in a liquid composed of 6 parts of 95 per cent
alcohol and 4 parts of distilled water. Dip articles in this liquid for a
moment and then remove and expose them to fumes of hydrogen sulphide
for five or ten minutes, or until they turn to a silvery gray. If they are not
evenly covered, remove, dry, dip again, and return to the fumes. When
the insect is evenly covered with a silvery gray finish, it is ready for the
bath.

63

The following bath is used for both formulae. Dissolve 1 pound of
copper sulphate in 2 quarts of warm water and add 2 ounces of sulphuric
acid; add slowly and stir constantly. Place the solution in a glass jar.
Use two 2-volt dry cell batteries in parallel. Connect several feet of fine
iron wire to the negative side of the battery, and to the other end attach
the article to be plated. The wire serves as a resistance wire. Attach
fine iron wire to the positive side of the battery and attach to it a sheet
of copper 3 by 4 inches for the anode. Leave the article in the bath for
12 to 24 hours or until the plating is heavy enough.

If the deposit is loose or grainy, use more resistance wire; if too slow,
use less wire but a slow deposit gives best results. If the article has spots
not plated, gild them carefully and return it to the bath until plated. Finish
the articles with such plating or bronze with gold or silver, or paint with
oils or enamel. To produce a metallic finish in colors, use combinations of
gold and silver for green, gold and copper for red. It takes practice to
master this coloring. After articles have been plated with copper, they may
be plated with silver by the "Electro" process in common use but a cheaper
process is as follows: use 60 grains of silver chloride, 300 grains of cream
of tartar, and 120 grains of common salt. Mix well and reduce to a fine
paste with distilled water; cover articles with this paste and let dry, rub
off with powdered chalk and polish. It takes a great deal of practice to use
this process efficiently.

Alcohol: Uses and Diluting

14. Dehydrating Alcohol (28) — By using anhydrous copper sulphate, water
can be removed from alcohol. Heat the copper sulphate in a pan until the
water is driven off and it becomes white. Place this in a receptacle or alcohol.
It will turn blue again as it picks up water. By repeatedly heating the copper
sulphate, the alcohol may be kept almost completely dehydrated. About
one third of the container of alcohol should be kept filled with crystals.
(For exact dilution table, see Bolles Lee (19), p. 45).

15. Testing Strength of Alcohol (28) — Post obtained the following hints
from J. Douglas Hood, Cornell University. If the solution is known to
be relatively free from oils, glycerin, and substances other than alcohol
and water, a sufficiently accurate determination may be made by a simple
specific gravity test. Take up a minute quantity of the liquid in a finely
pointed pipette and force it slowly into an alcohol of known strength. If
observed against the light it will be seen to sink or rise, depending on
whether it is heavier (weaker) or lighter (stronger) than the liquid in which
it is being tested. Differences as little as 5 per cent in water content may
be readily detected. The method is particularly valuable when the amount
of liquid available is too small to permit the use of a hydrometer.

16. Diluting Alcohol — Using 95 per cent alcohol, fill a graduate flask
to the number of cubic centimeters equal to the grade of alcohol desired
and fill up to the 95 cc. mark with distilled water. To make 75 per cent
alcohol from 95 per cent alcohol and water, pour 75 cc. of 95 per cent
alcohol into a graduate and fill to 95 cc. with distilled water.

64

17. Attaching Gummed Labels to Glass (38) — To attach gummed labels
to glass slides or bottles, apply a drop of alcohol to the non-gummy side
to make the label lie smoothly without wrinkling. Partly attached labels may
be refastened by the same method.

Soldering to Reduce Heat

18. Bismuth Solder (35)

Lead 3 parts

Tin ti 5 parts

Bismuth 8 parts

This solder has a low melting point, which may be lowered further by
adding mercury or cadmium. Use it to solder the wires in small leaves to
those in the branches, where normal soldering heat might run up the wires
and melt the casts.

19. Soldering Flux for Cleaning Subject before Soldering — Cut hydrochloric

acid by placing pieces of sheet zinc in the acid. Do not inhale the fumes.

For fine work, use jewellers' solid-core solder.

Preserving Leaves, Stems, Fruit, and Vegetables in Liquid

20. Copper Acetate (Boiling) for Preserving Green Colors in Plants (10) —
Securing a permanent approximation of natural color in green specimens is
often desirable, and can be accomplished by boiling the specimens in copper
acetate solution. To make stock solution add copper acetate crystals to a
50 per cent solution of glacial acetic acid until no more will dissolve. To
make solution for treatment, to 1 part of the stock solution add 4 parts of
water. The treatment is as follows:

• Heat the solution for treatment to just below boiling. While heating,
place the material to be treated into the solution. At this temperature the
green of the chlorophyll breaks down and a yellowish green or brown color
appears. As boiling continues the green color of the copper acetate replaces
the yellowish green or bleached foliage.

• The treatment may take 3 to 15 minutes. Fleshly parts may take about
30 minutes. When the proper intensity of color is reached, remove the
specimen from the hot solution.

• Thoroughly wash the specimen in tap water.

• After washing, place in a weak solution of formalin made by adding
5 parts of 40 per cent formalin to 95 parts of water. The strength of the
solution may be reduced to 3 per cent.

• After the specimens have been in the formalin solution for several weeks,
replace the solution at intervals of several weeks until it remains clear. Red
usually disappears and there is no known good method to preserve it, but all
shades of green and yellow are well differentiated by this method.

21. Copper Chloride (Cold) for Preserving Green Color in Plants (10) — The
following solution is valuable for preserving green, yellow, and red colors.

65

It is much more easily handled than the copper acetate solution and the
specimens are not boiled.

Alcohol (50 per cent) 90 cc.

Formaldehyde (40 per cent) 5 cc.

Glycerin 2.5 cc.

Glacial acetic acid 2.5 cc.

Copper chloride 10 gm.

Place the plants in the solution for several days. The full green color
is reached in two days by delicate plants and in three to ten days by harder
plants. Dry herbarium specimens treated by this method before pressing
retain their color indefinitely.

22. Preserving Fruit (10) — The various colors of fruits may be preserved, at
least partially, by placing the fruits permanently in the following solutions.

• For peaches, apricots, quinces, cherries, green and yellow pears, white
raspberries, green and yellow grapes and white currants:

Sulphurous acid 1 pint (0.568 1. )

Water 8 pints (4.544 1. )

Alcohol 1 pint (0.568 1. )

• For gooseberries, blackberries, red and yellow apples, red and black
cherries, red and black currants, red and black grapes, dark-coloured plums,
and red and black raspberries:

Boric acid 1 lb. (453.6 gm.)

Water 45 lb. (20.61 1. )

Alcohol 5 pints ( 2.74 1. )

Dissolve the boric acid in the water and then add the alcohol. If the
fluid is not clear, allow the suspended material to settle, decant, and filter.

23. Bleaching Woody Material (10) — To bleach woody roots or stems and
twigs of woody plants, place the specimens in 1 per cent sodium bisulphite
solution in jars. Add a little citric acid until a strong odor of sulphur dioxide
is given off. Leave the specimens in the solution for several weeks, until it
becomes discolored. Replace the solution until discoloration is not notice-
able. More delicate specimens may be bleached in the solution for one or
two hours and permanently preserved in 3 to 5 per cent formaldehyde.

Preserving Red in Fruits and Vegetables

24. Vacha's Formula 14A (43) — Useful for preserving red:

Cobalt nitrate 15 gm.

Stannic chloride 10 gm.

Formaldehyde (40 per cent) 25 cc.

Water 2000 cc.

This solution may be used for preserving strawberries, Bliss Triumph
potatoes, and other red fruits and vegetables. Thoroughly wash the speci-
mens in cold water, place them in jars, and submerge them in the solution.
Keep them in the solution for at least two weeks; discard the solution and
replace it with a holding solution, Vacha's Formula 14B, as follows:
Formaldehyde (40 per cent) 10 cc.

66

Ethyl alcohol (95 per cent) 10 cc.

Sulphurous acid 30 to 50 cc.

Water 1000 cc.

25. Vacha's Formula 2 (43) — Useful for preserving red raspberries and
red plums:

Potassium bisulphate 40 gm.

Oxalic acid 20 gm.

Formaldehyde (40 per cent) 30 cc.

Glycerin 50 to 150 cc.

Ethyl alcohol (95 per cent) 25 cc.

Water 1000 cc.

Place the specimens in the solution for about five days to three weeks,
and then in a holding solution, Vacha's Formula 14B.

26. Preserving Red in Fleshy Plants (43) — Vacha's Formula 41 is suitable
for preserving red in materials that are fleshy and soft and have a tendency
to break up:

Ethyl alcohol (95 per cent) 254 cc.

Formaldehyde (40 per cent) 54 cc.

Copper sulphate 0.5 gm.

Water 2500 cc.

Place the specimens in the solution for 24 hours to several days.
As soon as the red becomes dense, remove the specimens, wash them
thoroughly for several minutes in running cold water, and place them in a
holding solution of Vacha's Formula 14B.

27. Hesler's Solution for Preserving Insect Injury on Fleshy Plants and Fruits

(28) — The San Jose scale and the pear psylla were preserved in the following
solution. There was little loss of color or shrinkage in insect injury to prunes.

Water 4000 cc.

Zinc chloride 200 gm.

Formaldehyde (40 per cent) 100 cc.

Glycerin 100 cc.

Preserving Color in Plants for Mounting

28. Preserving Plant Material before Pressing (28)

Glycerin 50 parts

Acetone 25 parts

Alcohol (95 per cent) 25 parts

After specimens have been in the solution two or three days, they may
be pressed and mounted. The plants remain green and pliable.

29. Preserving Green Plants (16)

Alcohol (50 per cent) 90 cc.

Formaldehyde (40 per cent) 5 cc.

Glycerin 2.5 cc.

Glacial acetic acid 2.5 cc.

Copper chloride 10 gm.

Uranium nitrate 1.5 gm.

67

For yellowish green plants the amount of copper chloride may be
reduced by half, especially for Spirogyra, young corn plants, the young needle
clusters of larch, and the like.

For general laboratory use, plant materials are merely dropped into the
solution and stored until needed. Some delicate forms are ready for study
in forty-eight hours. Generally, however, the color change in most plants
is less rapid, and three to ten days are necessary to complete preservation.

Herbarium dry mounts made from specimens preserved in this solution
withstood fading, although exposed in a south window for eight months.
Plants preserved in this solution may also be kept in a 4 per cent formalde-
hyde solution.

30. Preserving Evergreen Foliage (29)

Ethylene glycol 65 parts

Water 34 parts

Carbolic acid or formaldehyde (40 per cent) 1 part
This solution has a specific gravity of 1.029, and penetrates better than
other solutions. Leave freshly cut evergreens in the solution for two weeks.

31. Fixing needles (29)

Gelatin 4 sheets

Water 12 ounces

Glycerin 3 cc.

Carbolic acid A few drops

Dissolve the gelatin in cold water. Warm the solution and add the
glycerin and the carbolic acid. Dip the branches as they come wet from the
glycol solution. Two or three dippings are necessary; shake the branches
well after each dipping.

Separators for Plaster Casts from Plaster Molds

32. Stearic Acid and Kerosene (41)

Stearic acid i lb.

Kerosene 1 pint

Aerosol O.T. 100 (Dioctyl sodium sulfo-

succinate) 1 oz.

Shave the stearic acid into flakes and mix the three ingredients. Bring
to the boiling point, but heat the mixture with care as it is very inflammable.
Stir well. Paint a very thin film while the solution is warm. If brush marks
show, thin with kerosene.

33. Petroleum Jelly (41)

Petroleum jelly 1 part

Kerosene 2 parts

Blend by heating and stir well.

34. Beeswax and Carbon Tetrachloride (7)

Yellow beeswax 1 part by weight

Carbon tetrachloride 9 parts by weight

Heat the carbon tetrachloride with the wax in it until the wax dissolves.

68

35. Banana Oil and Acetone (7)

Banana oil 3 parts by weight

Acetone 1 part by weight

This dries quickly on the mold.

36. Benzene and Paraffin (7)

Benzene 5 parts by weight

Paraffin 1 part by weight

This may be thinned by adding more benzene.

Separator for Wax Casts from Plaster Molds

37. Castile Soap

Liquefy 2 ounces of castile soap by boiling in 30 ounces of water to form
a stock solution. Add 3 teaspoonfuls to each gallon of water in which white
plaster molds are heated.

Base Construction

38. Papier mache (7)

Wet paper pulp 1 part by weight

Water 3 parts by weight

Plaster of paris 8 parts by weight

Hot glue (consistency for cabinet

work) 1 part by weight

Macerate paper such as old newspapers in boiling water. When the
fibres have separated, squeeze some of the water from the paper and add the
hot glue. Stir into a soft, sticky mass. Add the plaster and squeeze through
the fingers to break all lumps. Use as soon as possible after making. The
surface may be kept moist by covering with a damp cloth. The mixture
adheres firmly, sets in three hours, and becomes firm as wood.

It is best to make a new mass each time it is needed, but it may be kept
for a time by adding a few drops of glycerin and methyl salicylate, phenol, or
sodium fluoride, and storing it in a tightly sealed jar.

39. Coarse Papier Mache (7)

Felt building paper Whiting

Dextrin Plaster of paris

Macerate the paper in boiling water. Dry-mix equal parts of the plaster
and whiting. Mix dextrin syrup (equal parts of dextrin and water boiled)
with equal parts of the damp paper and the plaster- whiting mixture. The
mixture should set in less than one hour. To retard setting, add more
dextrin syrup and whiting; to hasten setting, add more plaster and dextrin.

40. Dextrin Mache for Touching up Tree Bark (4)

Dextrin 4 parts

Water 4 parts

Boil and add paper pulp 5 parts

Manikin sawdust 1 part

69

Mix the following thoroughly before adding to the above:

Whiting 7 parts

Plaster 7 parts

Stir all ingredients together until a smooth mass results.

41. Asbestos Mache

Ground asbestos 5 parts

Plaster of paris 1 part

Mix the asbestos and plaster thoroughly, then add 10 per cent glue until
a smooth medium like thin putty is obtained. When the mache is dry on
the base, paint it with 20 per cent glue.

Thinners for Airbrush Oil Painting

42. Turpentine-Linseed Oil Thinner

Pigment as it comes from the tube 1 part

Spirits of turpentine 2 parts

Linseed oil 1 part

43. Turpentine-Carbon Tetrachloride* Thinner

Spirits of turpentine 2 parts

Carbon tetrachloride 1 part

Damar varnish A few drops

For less gloss, use less turpentine and varnish.

* If desired, the very toxic solvent carbon tetrachloride may be replaced by methyl
chloroform (1,1,1, trichloroethane).

Preserving Natural Soil Units for Bases

44. Preserving with Lacquer Cotton — Dissolve lacquer cotton with acetone
or butyl acetate and pour the solution over a small soil area in the field.
When dry, lift the shallow section out intact. If acetone is used as a solvent,
it will set under water, or under wet conditions. Acetone sometimes leaves
a fog; if this happens, remove it with butyl acetate.

Methods for Casting in Plastic

45. Casting in Liquid Cellulose Nitrate (48)

Amyl acetate, technical grade 5 parts by weight

Cellulose nitrate 1 part by weight

Dissolve the cellulose nitrate in the amyl acetate. Two or three days
are required to dissolve the cellulose, with occasional stirrings.

46. Softening Cellulose Nitrate Sheets (26)

Acetone 60 per cent by volume

Water 40 per cent by volume

Immerse the sheet of cellulose nitrate in the solution until it is rubbery.

70

47. Rendering Bits of Plaster on Plastic Casts Transparent (48)

Benzene 5 parts

Linseed oil 1 part

Brush over the bits of plaster on the casts that cannot be removed by
brushing. They will become inconspicuous.

48. Retouching Plastic

Toluene 5 parts by weight

Ethyl cellulose 1 part by weight

Dissolve the cellulose in the toluene and tint with oil colors.

EQUIPMENT AND MATERIALS

Some exhibits may be prepared with a minimum of equipment, but
appropriate tools greatly facilitate the work and produce higher-quality
results. "Sources of Equipment and Materials" (p. 77), gives a ready index
to supply houses. Commonly used items are listed below.

Laboratory Facilities

Compressed Air — A cylinder of liquid carbonic acid gas is suitable for
operators working away from the laboratory, or when doing a limited amount
of spraying. Electrically driven compressors are much preferred for con-
tinuous use.

Fume Hood or Exhaust Fan — Fumes from solvents used in plastic casting
may be very objectionable and some may be harmful.

Benching — Work benches of two heights, 30 inches and 36 inches, are desir-
able. These should be supplied with outlets for water, gas, compressed air,
and vacuum.

Lighting — Lighting is very important. A room with north windows is best
for color work; use daylight bulbs.

Storage Space — Without proper temporary storage facilities, it is difficult to
care for unfinished material. Ample drawer space of different depths should
be available.

Mold Making

Equipment

A set of flat enamel, earthen, or glass bowls for mixing plaster

Boxwood modelling tools, steel rules

Metal ladle for babbit or antimonial lead

Tools such as shown in Figs. 58 and 59 (see p. 72).

Materials

Molding plaster, dental plaster, and dextrin
Water clay and plasticine

71

6 7 8

Figure 58-
(6) dental

Figure 59
(5) ruling

-d) Scissors, (2) forceps, (3) scalpel, (4) combination knife, (5) wax spatulas,
probe, (77 spoon and seeker, (8) dissecting needle, (9) holder for razor-blade
splinter, (10) Swiss pattern files.

— (1) Proportional divider, (2) caliper, (3) micrometer caliper, (4) dividers,
pen, (6) swivel stencil knife, (7) flexible spatula, (8) cutting forceps, (9) long-
nosed cutting pliers.

Castile soap, borax, alum, and talc

Tin for leaf mold forms

Liquid latex and ammonia for dilution

Water-white kerosene for enlarging latex molds

Gelatin for molds

Babbit metal or antimonial lead for metal molds

Molders' sand

Casting in Wax

Equipment

Electric hot plate, Bunsen burner, and alcohol lamp

Enamel double boilers for melting wax, enamel pan for heating plaster

molds in water

Water pitchers and ladles for wax

Pipettes

Wax press for casting leaves (Fig. 60.)

Materials

Pure white beeswax, paraffin wax
Castile soap

72

Long-fibred absorbent cotton and cheesecloth
Annealed iron, copper, and monel wire
Stearic acid for a separator

Casting in Plastics

Equipment

Small brass brushes for removing bits of plaster from casts

Air-tight box for holding unfinished casts over noon hour or night to

retard drying
Tray of brushes in solvent for applying liquid plastic (Fig. 61.)

Materials

Cellulose nitrate and cellulose acetate sheets for preparing liquid plastic

and for casting in press molds

Ethyl cellulose in low-viscosity, granular form, to be dissolved in toluene

for retouching plastic casts

Cellulose butyrate tubes and rods for model making

Crystals of "Gelva" and "Alvar", synthetic resins for impregnating

plaster casts

Tenite pellets and sheets for thermocasting

Methyl methacrylate for building up thick midribs in large leaf casts

Solvents: amyl acetate, butyl acetate, ethyl acetate, acetone, diacetone

alcohol, and toluene

Art Work

Equipment

An airbrush that will produce a fine line as well as a wide spray is very
useful (Fig. 62, p. 74).

Binocular microscope, hand lens, and mounted, adjustable, rectangular
swivel lens

Figure 60 — Hand-press for casting leaves. Figure 6 7 — Tray of brushes in solvent

for casting in liquid plastic; the stoppers
are fixed to the handles.

73

54899-0—6

Figure 62
Airbrushes.
Left, Wold
Center, Thayer and
Chandler.

Right, Paasche.

Figure 63

Electric drill

with flexible shaft

and grinder.

Drafting board, T-square, and ruling pens

Artists' sable brushes for oil paint, Nos. 00 to 10, and white bristle

brushes with unpainted handles for plastic casting, Nos. 3 to 10.

Materials

Artists' tube oil colors with thinners: rectified spirits of turpentine and

carbon tetrachloride

Artists' dry paints in various colors

Tracing paper

Assembling Exhibits

Equipment

Electric soldering iron with 1-inch point; high-speed electric drill with
flexible shaft, and chuck taking drill bits and attachments from zero
to i inch (Fig. 63.)

74

Materials

Adhesives: "Duco" household cement, "Ambroid" cement, "Kodak"

rapid mounting cement, book-binders' paste, liquid glue, gum traga-

canth, and gum arabic

Jewellers' solder

Zinc sheet and hydrochloric acid for soldering flux

Ground asbestos for mache mix

Collecting Insects

Equipment

Insect net, killing bottles, glass jars, and tins for carrying living and
dead insects in the field; lantern breeding cage for rearing larvae in the
laboratory (Fig. 1, p. 7).

Inflating Larvae

Equipment

Double-bulb cautery set to ensure steady air pressure within the skin

(Fig. 64, p. 76).

Alcohol lamp and tin box with opening on one side for inserting the

skin while drying. (This improvised oven should be soldered to a wire

frame to hold it above the flame. An infra-red lamp may be used in

place of the alcohol lamp and the oven.)

Fine curved and straight forceps, dissecting needles, glass cannulas

(small glass tubes drawn to fine points), clips made from watch springs

fastened to the cannulas with silk threads

Collecting Plants

Equipment

Trowel for securing roots with plants

Oval tin box about 16 inches long with a long, tight-fitting, hinged door,

keeping plants fresh between sheets of wet paper (Use shoulder straps

for carrying vasculum)

Two slatted wood frames, 12 by 17 inches with metal slots through

which to pass webbing straps for pressing the plants (Fig. 65, p. 76).

Porous felt paper, 12 by 17 inches, for absorbing moisture from the

drying plants, ventilating with sheets of corrugated paper between the

porous felt paper sheets

Good grade bristol board or 56-pound ledger paper cut to 161 by Hi

inches for mounting dried plant specimens. Mounting tape may be

gummed paper, cloth, or transparent plastic; "Gelva" solution may be

used for mounting. Herbarium labels are white, gummed paper about

2i by 4 inches, usually having headings similar to the following:

Family

Scientific name

Common name

Locality

Habitat

75

54899-0—6*

Date Det.

No Collector

See mounted specimen (Fig. 2, p. 7).

Preserving Plants

Materials

Acids: glacial acetic, hydrochloric, oxalic

Gelatin and formaldehyde

Copper acetate, copper chloride, and copper sulphate

Potassium bisulphate, zinc chloride, cobalt nitrate, uranium nitrate

Miscellaneous

Equipment

Small bench vise, hand saw, hack saw and blades, hand drill and bits
Emery wheel, oil stone, screwdrivers, hammers, chisels, smoothing
plane, tri-square, files, countersink

Materials

Ethyl alcohol, methyl alcohol, benzene, ether, chloroform, carbon tetra-
chloride, xylol

Figure 64

Cautery set

and glass

cannulae with

spring clips

for inflating

larvae.

64

Figure 65

Plant press

with driers and

ventilators.

76

APPENDICES

A— SOURCES OF EQUIPMENT AND MATERIALS

(The number or numbers after each item refer to the appended list of

supply houses.)

EQUIPMENT

Air compressor 45, 77

Airbrush 2, 9, 61, 75, 82

Bits 45, 77

Botanical driers and ventilators 21, 40

Bowls, enamel 45

Bowls, glass 45

Brace 45, 77

Brushes, brass 45, 77

bristle 9, 10, 47, 66

sable 9, 10, 47, 66

Bunsen burners 45, 77

Caliper, graduate 47, 48

micrometer 47, 48

Carbonic acid gas unit 70

Cautery set 18, 21, 37, 40, 81

Chisels 45, 77

Countersink 45, 77

Dividers, pointed 47, 48

proportional 47, 48

Double boilers 45

Drafting board 47

Drills, hand 45, 77

speed 45, 77

Emery wheel 45, 77

Fan, exhaust 34

Files, fiat and 3-cornered 45, 77

Swiss pattern 49

Foam rubber 42

Gas burner 45, 77

Glass blowing, tools for 33

Hammers 45, 77

Hot plate 34

Ladles, for metal 14

for wax 45, 77

Lamps, alcohol 18, 21, 37, 40, 81

desk 34

infra-red 34

Lenses, pocket 5, 47

swivel rectangular 5, 47

Micrometer, caliper 47, 48

Microscope, binocular 5

Modelling tools 9, 10, 18, 21, 37, 40, 81

Needle holders 18, 21, 37, 40, 81

Oil stove 45, 77

Pan for heating molds 45

Pens, ruling 47, 48

Pipettes 18, 21, 37, 40, 81

Pitchers 45

Plant press 21, 40

Rules 45, 47, 77

Saws, hack 45, 77

hand 45, 77

Scalpels 18, 21, 37, 40, 63, 81

Scissors 18, 21, 37, 40, 63, 81

Screw drivers 45, 77

Soldering iron, electric 45, 77

Spatulas 18, 21, 37, 40, 63, 81

Specimen hangers, Schrosbree 56

Square, T 47

Tri 45, 77

Thermometers 18, 21, 37, 40, 81

Trimmers, paper 32

Tweezers 18, 21, 37, 40, 81

Insect net 18, 21, 37, 40, 81 Vasculum 18, 21, 37, 40, 81

77

MATERIALS

ADHESIVES

Adhesives, general 45, 77

Cement, "Ambroid" 3

"Duco" 45, 77

high speed 45,77

"Kodak" rapid mounting 32

rubber 45, 77

Glue, liquid 45, 77

Paste, bookbinders' 12

Plaspreg 39

ART

Airbrush supplies 2, 9,61,75,82

Oil, linseed, raw, and boiled 45, 77

white kerosene 45, 77

Paint, artists' dry 9, 10, 47, 66

artists' oil 9, 10, 47, 66

water colors 9, 10, 47, 66

Pearl essence 51, 55

Pearl spray 66

CHEMICALS (13, 29, 58, 68)

Acid, glacial acetic

nitric

stearic

sulphuric

sulphurous

Alum

Ammonia

Arsenious oxide

Borax

Calcium cyanide

Camphor gum

Copper acetate

chloride

sulphate

Ether

Ethylene glycol

Gelatin

Glycerin

Gum arabic

camphor

tragacanth

Mercuric chloride

Petroleum jelly

Phenol

Potassium cyanide

Soap, castile

green

Sodium carbonate

Vaseline

GENERAL SUPPLIES

Babbitt metal 14

Cheesecloth 30

Enamel, flat white, special EK 368 53

Glassware 18, 21, 37, 40, 81

Hippo oil 1,45,77

Pins, insect 40, 80

steel 73

Rubber, raw 42

Shellac, orange, white 45, 77

Solder, jewellers' 49

Tin boxes 18, 21, 37, 40, 81

Varnish, Damar 45, 77

Vise 45, 75

Wire, annealed iron 45, 77

copper 45, 77

magnesium 63

monel 43

MOLDING AND CASTING

Aerosol OT-100 (dioctyl sodium sulfo-

succinate) 37

Asbestos, ground 45, 77

Beeswax, refined white 50, 54, 58, 71

Clay, water 76

Dextrin 25

Flocks, cotton 8

rayon 22

wool 36

Glass for blowing 33

Hydrocal cement 78

Latex, liquid 4, 41, 52, 67

Molding compound 62, 67, 80

Paraffin wax 45, 77

Petroleum jelly 29

Plaster, casting 14, 16, 44, 78

Coecal 27

molding 14, 16, 44, 78

Plasticine 73

Pumice, ground 45, 77

Sculpture supplies 35

PLASTICS

Alvar 69

Butyrate rods and tubes 60

Cellulose acetate 6,17,31,39,57

butyrate 60

nitrate 6, 17, 31, 39, 57

Embedding plastic 80

Gelva 69

Lacquer cotton No. 1 46

Methyl methacrylate 26, 68

Plaspreg 39

Plexiglass 23

Tenite, pellets 74

sheets 74

SOLVENTS (13,29,58,68)

Acetic ether

Acetone

Amyl acetate

Benzene

Butyl acetate

Carbon tetrachloride

Chloroform

78

Diacetone alcohol
Dibutyl phthalate

Ether

Ethyl acetate

Ethyl alcohol

Formaldehyde

Methyl hydrate

Toluene

Turpentine, spirits of
Xylol

B— SUPPLY HOUSES

10.
11.

12.

13.

14.
15.

16.

17.

18.

19.

20.

21.

22.

23.

24.
25.

26.

27.

28.
29.
30.

Acme Paint & Varnish Co. Ltd., New
Toronto, Toronto, Ont., and Montreal,
Que.

Airbrush and accessories supply houses
Ambroid Co., 305 Franklin St., Boston
10, Mass.

American Anode Corp., 60 Cherry St.,
Akron, Ohio.

American Optical Co., Buffalo 15, N.Y.
Anthony-Foster & Sons Ltd., 294-306
Church St., Toronto, Ont.
Armstrong Cork Insulation, Adhesive
Div., 522 King St. W., Toronto, Ont.
Arthur Brown Co., 2 West 46th St., New
York, N.Y.

Art Metropole, 36 Adelaide St. W.,
Toronto, Ont.
Art supply houses

Ash-Temple Dental Supplies, Box 249,
London, Ont.

Bookbinding houses, or No. 2863 Swift
Canadian Co., Toronto 9, Ont.
British Drug Houses (Canada) Ltd.,
Toronto 14, Ont. (through local stores)
Builders' supplies

Canadian Durex Abrasives Co., Brant-
ford, Ont.

Canadian Gypsum Co. Ltd., 170 Bloor
St., Toronto 5, Ont. (through local
builders' supplies)

Canadian Industries (1954) Ltd., Box 10,
Montreal, Que.

Canadian Laboratory Supplies, Ltd., 3701
Dundas St. W., Toronto 9, Ont.
Carver Hydraulic Press Co., New York,
N.Y.

Cave and Co. Ltd., 567 Hornby St.,
Vancouver 1, B.C.

Central Scientific Co. of Canada Ltd.,
146 Kendal Ave., Toronto 4, Ont.
Claremont Waste Mfg. Co., Claremont,
NJ.

Colonial Kalonite Co., 2212 Armitage
Ave., Chicago, 111.

Corning Glass Works, Corning, N.Y.
Corn Products Sales Co., 333 N. Michi-
gan Ave., Chicago, 111.
Crystal Glass and Plastics Ltd., Queen's
Quay, Toronto, Ont.

Dental Co. of Canada Ltd., 229 College
St., Toronto, Ont.
Dow Chemical Co., Midland, Mich.
Drugstores
Dry goods stores

31

32

40

41

42

Du Pont Co. of Canada Limited, 80

Richmond St., Toronto, Ont.

Eastman Kodak Co. Ltd., Rochester,

N.Y.

Canadian Kodak Co. Ltd., Toronto, Ont.

33. Eisler Engineering Co., Newark, N.J.

34. Electrical supply stores

35. Ettl Studios, 227 W. 13th St., New York,
N.Y.

36. Favor Ruhl & Co. Inc., 425 South
Wabash Ave., Chicago, 111.

37. Fisher Scientific Co. Ltd., 904 St. James
St., Montreal, Que., and 245 Carlaw Ave.,
Toronto 8, Ont.

38. Foundries

39. Furane Plastics Inc., 4516 Brazil St., Los
Angeles 39, Cal.

General Biological Supply House Inc.,
761-763 E. 69th Place, Chicago, 111.
General Latex and Chemical Corp., 666
Main St., Cambridge, Mass. (Canada),
Montreal, Que.

Goodrich, B. F., Rubber Co., Dunker
Bldg., Kitchener, Ont.

43. Greening, B., Wire Co., Hamilton, Ont.

44. Gypsum, Lime and Alabastine Co., Paris,
Ont.

45. Hardware stores

46. Hercules Powder Co., Wilmington 99,
Del.

47. Hughes-Owens Co., 527 Sussex St., P.O.
Box 77, Ottawa, Ont.

48. Instruments Ltd., 240 Sparks St., Ottawa,
Ont.

Jewellers' supplies
Jones and Son, Bedford, Que.
Knob-Loch Co., 4726 Arthington St.,
Chicago, 111.

Latex Laboratories, 2336 N. Hoyne Ave.,
Chicago, 111.

Lowe Bros. Co. Ltd., 263 Sorauren St.,
Toronto, Ont.

Mailloux, J. E., Ltee, St. Jean, Que.
Mearl Corp., 153 Waverly Place, New
York, N.Y.

56. Milwaukee Pub. Museum, Milwaukee,
Wis.

57. Monsanto (Canada) Ltd., 183 Front St.,
Toronto 2, Ont.

National Drug and Chemical Co.,
London, Ont., and Montreal, Que.
National Lead Co., Chicago, 111.
Ontario Steel Products, Plastic Div.,
Gananoque, Ont.

79

49
50
51

52

53

54
55

58.

59.
60.

61. Paasche Airbrush (Canada) Ltd., 864
Pape St., Toronto, Ont.

62. Perma-Flex Mold Co., 243 Fifth St.,
Columbus 15, Ohio.

63. Physicians supply houses

64. Polymer Corp. of Pennsylvania, Dept.
SM, Reading, Penn.

65. Popper, Leo and Son, Importers, New
York, N.Y.

66. Professional Art Products Co., Dept. SM,
8455 Wabash Ave., Chicago, 5, 111.

67. Robbins, Jim, Co., 130 Stephenson High-
way at 14 Mile Rd., Royal Oak, Mich.

68. Rohm and Haas Co., Washington Square,
Philadelphia 5, Penn.

69. Shawinigan Chemicals Ltd., Chemical
Div., Shawinigan Falls, Que.

70. Soda fountain supply houses

71. Soden, P. N. and Co. Ltd., 1498 Yonge
St., Toronto, Ont.

72. S. S. Rubber Co., 314 N. Michigan Ave.,
Chicago, 111.

73. Stationery stores

74. Tennessee Eastman Corp., 360 N. Michi-
gan Ave., Chicago, 111.

75. Thayer and Chandler, 910 W. Van
Buren St., Chicago, 111.

76. Tile yards

77. Tool shops

78. United States Gypsum Co. (through
local dealers)

79. United States Plywood Corp., Dept. SM,
Weldwood Bldg., 55 W. 44th St., New
York, N.Y.

80. Ward's Natural Science Estb. Inc., 3000
Ridge Rd. E., Rochester, N.Y.

81. Wills Corp., Rochester 3, N.Y.

82. Wold Air Brush Mfg. Co., 2173 N.
California Ave., Chicago, 111.

C— REFERENCES

1. Beirne, B. P. Collecting, preparing, and preserving insects. Canada Dept. Agr. Pub. 932.

1955.

2. Berg, C. O. Alizarin staining and embedding of stained specimens in transparent plastic.

Ohio Wesleyan Univ., Delaware. (Mimeographed manuscript)

3. Blakely, D. M. Preserving coniferous foliage. Cranbrook Museum, Bloomfield Hills,

Mich. (Personal communication)

4. Butler, A. E. Building the museum group. Amer. Mus. Nat. Hist. Guide Leaflet Series

No. 82. 1934.

5. Carmel, J. Constructing animated models. Cranbrook Museum, Bloomfield Hills, Mich.

(Personal communication, 1953)

6. Castolite Company, Manual No. 1. Basic instructions for using Castolite plastics. Wood-

stock, 111. 1949.

7. Clarke, C. D. Molding and casting. John D. Lucas Co., Fayette, East and Laurel Sts.,

Baltimore, Md. 1940.

8. Fessenden, G. R. Preservation of agricultural specimens in plastics. U.S. Dept. Agr.

Misc. Pub. 679. 1949.

9. General Biological Supply House. Preserving botanical specimens. Turtox Leaflet 3.

Chicago, 111. 1935.

10. Granovsky, A. A. Methods of collecting and preserving of insect injuries. Univ. of

Minnesota, St. Paul, Minn, (mimeographed manuscript)

11. Gunder, J. D. Blowing eggs of Lepidoptera. Can. Ent. 60 : 1. 1928.

12. Hall, D. G. Preserving small soft-bodied insects. Ent. News. 1933.

13. Hetrick, L. A. Preserve life-history specimens in this gelatin-formaldehyde preparation.

Ward's Ent. Bull. 6 (5) : 4. 1939.

14. Hornaday, W. T. Taxidermy and zoological collecting. Chas. Scribner's Sons, New York,

N.Y. 1892.

15. Kadel, G. W. Airbrush art. Signs of the Times Pub. Co., Cincinnati, Ohio. 1946.

16. Keefe, A. M. A preserving fluid for green plants. Science 64 : 331-332. 1926.

17. Laybourne, E. G. Recent uses of the Walters method in taxidermy. Mus. News 11:6.

1934.

18. Laybourne, E. G. A detailed account of reproducing a water snake. Mus. News 12 : 17.

1935.

19. Lee, Bolles (J. B. Gatenby & H. W. Beams, editors). The microtomist's vade-mecum.

11th ed. The Blakiston Company, Philadelphia, Pa. 1950.

20. Lutz, F. E. The new insect groups in the American Museum. Nat. Hist. 25 : 126-135.

1925.

21. Marioni, D. Conservation and restoration of entomological collections. Lab. Ent. Agr.

Pontici Boll. 11 : 234-242. 1952.

80

22. McCabe, J. A. Museum cases to minimize fatigue. Mus. News 10 : 18. 1933.

23. McDunnough, J. H. Directions for collecting and preserving insects. Canada Dept. Agr.

Pub. 520 (Cir. 110). 1947.

24. Nicholls, C. P. Preparing display cases. Belleville, Ont. (personal communication, 1951)

25. Parker, G. H. Preparing contact prints for exhibition labels, (personal communication,

1956)

26. Petersen, G. Preparing artificial foliage in wax and celluloid. Amer. Mus. Nat. Hist.,

New York, N.Y. (personal communication, 1946).

27. Peterson, A. A manual of entomological technique. Edwards Bros. Inc., Ann Arbor,

Mich. 1953.

28. Post, R. L. Preserving insect specimens and preparing material for display. North

Dakota Agr. College, Fargo, (mimeogiaphed manuscript, 1948)

29. Raizenne, H. An improved method in the preparation of coniferous foliage for exhibition

purposes. 71st Ann. Rept. Ent. Soc. Ontario, 1940, pp. 51-52. 1941.

30. Raizenne, H. The use of thermo-setting plastic for the preservation of leaves in natural

color. Canada Dept. Agr., Div. Ent. Processed Pub. 108. 1949.

31. Reid, A. Steps in making durable lightweight casts of latex. In Report of the Director

for the year ended June 1955, pp. 5-9. Royal Ontario Mus. Zool. and Palaeontol.,
Toronto. 1955.

32. Ross, D. A., and J. K. Harvey.* Note on infra-red lamp for drying inflated larvae. Can.

Ent. 86 : 158. 1954.

33. Ross, H. H. How to collect and preserve insects. Illinois Nat. Hist. Survey. Circ. 39.

1949.

34. Rowell, A. L. A brief outline of method of casting miniature foliage. Chicago Mus. Nat.

Hist, (personal communication, 1949)

35. Rowley, J. Taxidermy and museum exhibition. D. Appleton and Co., New York, N.Y.

1925.

36. Scott, A. W. Metal plating insects. Ward's Ent. Bull. 6 (4) : 4. 1939.

37. Silver, J. C. Apparatus and method of filling lepidopterous larvae with wax. U.S. Dept.

Agr., Bur. Ent. Plant Quar. ET-122. 1938.

38. Smith, M. E. Attaching gummed labels to glass. Ward's Ent. Bull. 13 (5) : 6.

Rochester, N.Y. 1940.

39. Stuttgart. Die Paedogenesis du Cecidomyiden. 1908.

40. Tobias, J. C. A manual of airbrush technique. American Photographic Publishing Co.,

Boston, Mass. 1946.

41. United States Gypsum Co. How to make patterns and models with gypsum cement.

Bull. IGL - 100. 300 West Adams St., Chicago, 111. 1946.

42. United States Gypsum Co. U.S.G. master caster. 300 West Adams St., Chicago, 111.

1946.

43. Vacha, G. A. Formulae for preserving colors in fruit and flowers. Univ. Minnesota,

St. Paul, Minn, (mimeographed manuscript).

44. Valentine, J. M. On the preparation and preservation of insects, with particular reference

to Coleoptera. Smithsonian Misc. Coll. 103 (6) : 1-16. 1942.

45. Von Fuehrer, O. F. Liquid rubber, a new casting medium. Mus. News 15 : 16. 1938.

46. Von Fuehrer, O. F. Latex in science and art. Museum News 24 : 19. 1947.

47. Von Fuehrer, Mrs. O. F. Uses of blown glass in constructing enlarged models. Carnegie

Museum, Pittsburgh, Pa. (personal communications, 1946)

48. Walters, L. L. New uses of celluloid and similar material in taxidermy. Chicago Nat.

Hist. Mus. Tech. Ser. 2. 1925.

49. Walters, L. L. and J. C. Moyer. Reproducing birds' feet in celluloid. Mus. News 10 : 17.

1933.

50. Walters, L. L. Preserving natural soil units for bases. Chicago Nat. Hist. Museum.

(personal communication, 1952)

51. Ward's Natural Science Establishment Inc. How to embed in bio-plastic. Rochester,

N.Y. 1950.

52. Wormser, W. S., and W. P. Hayes. The permanent preservation of insects. Brooklyn

Ent. Soc. Bull. 31 : 111-128. 1936.

See also: Harvey, J. K. Improved technique for inflating and mounting insect larvae. Can.
Ent. 89 : 280-283. 1957.

81

D— GLOSSARY

Accelerator — A substance used in the water
for a plaster mix to shorten the setting time.

Adhesive — Adhering, sticky.

Airbrush — An instrument for spraying paint
on a surface.

Air compressor — A unit to pump air into a
storage tank to supply a continuous flow of
air at a given pressure regulated by an air
gauge.

Alvar — A synthetic resin soluble in alcohol.

Anhydrous — Lacking the water of crystalli-
zation (applied to minerals).

Anther — The essential part of the stamen
which contains the pollen.

Anode — The positive pole of an electric
source.

Antennae — The jointed feelers on the heads
of insects.

Apron — A projection on the inside top of a
diorama to cut off view of ceiling join.
See Fig. 42, p. 49.

Armature — A framework to strengthen a
model.

B

Binding post — One of the metal posts holding
the sheets in place in a loose-leaf binder.

Blade — The expanded portion of a leaf.

Bloom — The delicate, powdery coating on
surfaces of many plants such as plums,
grapes, and cabbage.

Blowpipe — A small glass tube drawn to a
fine point, with rubber tubing attached to
one end; used to empty egg shells.

Buffing plastic casts — The act of removing
gloss from the casts with a brush and
ground pumice.

Bunsen burner — A kind of burner consisting
of a straight tube, 4 or 5 inches long, with
small holes for entrance of air at the
bottom. Illuminating gas is also admitted
at the bottom; a mixture of gas and air is
formed which burns at the top with a
feebly luminous but intensely hot flame.

Caudal — Of, or pertaining to, the cauda or
the anal end of the insect body.

Cautery set — As used for inflating insects, a
hand blower giving a continuous stream of
low-pressure air; the first bulb is the
"pump" for putting air in the second bulb,
which is balloon-like and covered with net.

Cc. — The volume contained in a cubic centi-
meter (one centimeter high and one centi-
meter on each side).

Celluloid — Usually a plastic that has been
plasticized with camphor.

Compound leaf — A leaf consisting of two or
more leaflets.

Coniferous — Cone-bearing; evergreen.

Corolla — The leaves of the flower within the
calyx.

Crisper — An enclosed container refrigerated
at above freezing to hold vegetation fresh.

D

Dam — A barrier around a subject to contain
plaster or other molding material.

Deciduous — Having leaves that fall in autumn.

Dehydrate — Deprive of water.

Diorama — A self-lighted display group with a
foreground of reproduced subjects and a
curved, painted background. It is used to
represent out-of-doors scenes.

E

Eccentric wheel — A wheel with an offset axle

and an arm to change rotary into backward

and forward motion.
Emboss — To cause to stand out; to model

between veins in paper leaves, causing the

veins to stand out in relief.
Enlarged model — A scale model made larger

than the original.
Essence of pearl — A medium made from fish

scales, using a plastic base.
Extrusion of plastics — Pressing plastics by

machine into tubes, rods, and various

patterns.

Calcined — Reduced to powder by heat.
Calyx — The outer set of floral envelopes of a

flower.
Cam — A projecting part on a wheel to

impart an alternating motion.
Cannula — A glass tube drawn to a fine tip.
Catalyst — As used for embedding in plastic: a

chemical compound that initiates the

process of polymerization, by which the

liquid plastic becomes solid.

Fascicle — A close cluster.

Filament — The stalk of a stamen in a flower.

Fistular — Cylindrical and hollow like onion

tops.
Flocks — Finely cut cotton, wool, or plastic

thread used to form pubescence on wax

plants.
Flower stalk — The stalk that holds the flowers;

the peduncle.
Fusible — Capable of being melted by heat.

82

Gamopetalous — Having united petals.

Gelva — A synthetic resin soluble in alcohol.

H

Halteres — Movable filaments or balancers in
Diptera, one on each side of the thorax
and representing the hind wings of 4-
winged insects.

Head capsule — The sclerotized portion of the
head of an insect.

Herbarium — A systematically arranged collec-
tion of plants.

Hydraulic press — One with the force exerted
by liquids.

Hydrometer — An instrument for determining
the specific gravity of fluids.

Impregnate — Infuse an active principle into.

Inflation of larvae — The emptying and drying
of larval skins and filling with air to dis-
tend them to natural size.

Integument — The body wall (of an insect).

Internode — The part of a stem between the
nodes, joints, or leaf attachments.

J

Japanese paper — A thin, tough, long-fibred
paper made in Japan.

K

Killing bottle — A stoppered bottle having a
lethal poison in the bottom such as
cyanide, ethyl acetate, or carbon tetra-
chloride.

Lacquer — A varnish consisting of shellac

dissolved in alcohol, or plastic dissolved in

a solvent.
Latex — The milky juice of plants; for molds,

a liquid preparation from the juice of the

rubber tree to dry in the air.
Leaf blade — The expanded part of a leaf.
Ligature tube — A vial of soft glass that can

be sealed with a blast lamp after insertion

of a specimen and preserving fluid.
Ligule — A membranous appendage at the

summit of a leaf sheath of grass.

M

Manikin — In museum work, an artificial fill-
ing for an insect or an inner reinforcement
for a hollow, plastic cast.

Masking tape — Sticky paper or cellulose tape
used for masking when spray painting.

Micrometer caliper — An instrument for meas-
uring minute distances or thicknesses.

Monomer — In embedding, a liquid, plastic
syrup. Adding a catalyst brings about
polymerization.

Mother mold — A sectional mold of plaster
around a flexible mold to hold its shape
during casting.

N
Node — A knob on a root or a branch; the
point from which leaves arise.

O

Oscillate — To swing back and forth; vibrate.
Ovipositor — A pointed, tubular organ with
which female insects deposit eggs.

Papier mdche — Molded paper pulp. Ground

asbestos and plaster may be used in place

of paper.
Period of plasticity — In plaster, the period of

free flowing.
Petal — A leaf of the corolla.
Petiole — The continuation of the midrib of a

leaf, or leaflet which is attached to the

rachis.
Pipette — A glass tube with a narrow tip.
Pistil — The seed-bearing organ of a flower.
Plant drier — Felt paper used in a plant press

to absorb moisture.
Plant press — Two slatted wood frames with

straps around them to press plants.
Plaster jacket — A sectional mold of plaster

around a flexible mold to hold its shape

during casting.
Pollen — The fertilizing powder contained in

the anther.
Polypetalous — Having the petals separate.
P.s.i. — Pounds' pressure per square inch.
Pubescence — The fine, soft hairs on plants.

Rachis — The central stem in a compound leaf
to which the leaflets are attached.

Receptacle — The axis or support of a flower.

Replica — A copy of an original.

Retarder — In plaster mix, a substance put in
the water to slow the setting time.

R.p.m. — Revolutions per minute.

Scribe — To make lines with a pointed
instrument.

Segment — Of an insect, one of the rings that
compose the body.

Separator — In molding and casting, a sub-
stance applied to plaster to prevent the
second pour from sticking, or to prevent
wax from adhering to a mold.

Seta — A stiff hair or bristle.

Sheath — The base of a leaf when surrounding
the stem, as in grasses.

Size — To glaze or coat with glue, starch, etc.

Soil profile — A vertical section of soil to show
types of soil or insects in the soil.

83

"Spaghetti" insulation — A small, fabricated

tube used as insulation in radio work.
Spatula — A knifelike implement with a broad,

flat, more or less flexible blade for mixing

drugs, paints, etc.
Specific gravity — Relative density.
Sludge — In casting, the scum forming on

melting metals.
Slurry — Mixed plaster thin enough to pour.
Solvent — The component of a solution that

dissolves the other component or com-
ponents.
Stalk or stem — The axis of a plant; the part

that bears all the other parts.
Stamen — The fertilizing organ of a flower.
Stipple — To dot.
Stipule — One of the appendages at the base

of the leaf in many plants.
Stria — A slight furrow or ridge.
Suture — A line of junction between two parts.
Swiss pattern file — A miniature file used by

watch makers.
Synchronous motor — An electric motor with

a set speed, as in clocks and record players.

Template — A pattern or gauge.

Turbine — In airbrushes, a wheel that spins by

air pressure.
Turntable — A revolving platform.

U

Undercut — A cavity with overhanging edges;
any part of a subject in which a rigid mold
will lock.

Vasculum — A kind of case or box used by

botanists for carrying specimens as they

are collected.
Viscera — The soft, interior organs of the body,

especially of the abdomen.
Vulcanize — In latex molds, to dry the

medium.

W

Waste mold — A plaster mold that is used

once and discarded.
Water clay — Usually a clay with a mixture

of sand that may be softened with water.

84

E— INDEX

Page

Acids 78

Adhesives 78

"Ambroid" cement 78

bookbinders' paste 78

"Duco" household cement 78

high speed cement 78

"Kodak" mounting cement 78

Airbrushes 77

air supply 48

brush types 47

care of 48

performance of 47

Air compressor 48

Alcohol 64

Alvar 78

Amyl acetate 29,78

Antimonial lead 20

Arabol bookbinders' paste 78

Arsenical soap 63

Arsenious oxide 78

Asbestos, ground 78

Assembly 37

models 45

plants 37

B

Babbitt metal ' 78

Barber's method 60

Beeswax 78

Breeding cages 1

Brushes 77

brass 77

oil paint 77

plastic casting 77

Bubbles in vials 4

Bunsen burner 77

Butyrate extrusions 78

rods 78

tubes 78

Page

Cellulose 78

acetate 78

butyrate 78

nitrate 78

Clay, water 78

Coecal plaster 78

Coldpress plastic 34

Coleoptera, preserving 6

Collecting 1

insects 1

plants 6

Color sketches 30

Coniferous foliage 40

ethylene-glycol solution 40

gelatin dip 40

Copper 78

acetate 78

chloride 78

sulphate 78

Coxhead-Liner 50,56

Cyanide 78

calcium 78

potassium 78

D

Degreasing insects 5

Dextrin 78

Dilution, chemical 64

Dioramas 48

background 49

base 49

foreground 49

lighting 50

shape 49

view window 49

Display units 50-54

Dividers 77

Drafting board 77

Drill, high speed 77

Duco cement 78

Calipers 77

Camphor gum 78

Carbonic gas outfit 48

Casting 22

in wax, hollow 23

in wax, solid 23

in plastic 28

wax larvae 28

wax leaves 26

Cautery set 3 77

E

Embedding in plastic 36

Emery wheel 77

Enlarged models 42-47

Equipment 77

Essence of pearl 78

Ether 78

Ethylene glycol 78

Ethyl acetate 78

Exhaust fan 77

85

Page
F

Flexible molds 14-18

gelatin 19

latex 14

Flocks

cotton 78

plastic 78

wool 78

Flux, soldering 65

Foliage 40

coniferous 40

deciduous 59

Formalin-chloroform solution 5

Formulae 60

Fruit preserving 65-67

G

Gelatin-formaldehyde 4

Gelva 78

Glue 78

Glycerin 78

Grasshopper exhibit 51

Gum 78

arabic 78

camphor 78

tragacanth 78

H

Hesler's solution 67

Holder for brushes 73

Hydrocal cement 78

Impregnating

insects 6, 12

plaster 14

I

Inflating 3, 63

larval skins 3

larval skins with wax 3

Insect eggs 2

Insect net 77

K

Kahle's fluid 61

Killing bottles 1

L

Labels 54

Lacquer cotton

Ladle

metal pouring 77

wax pouring 77

Lamp

alcohol 77

desk 77

infra-red 77

Latex 78

enlarging molds 18

potato molds 14

Page

reinforcements 17

separators 15

solvent 15

Lens 77

pocket 77

swivel rectangular 77

Lepdioptera, preserving 5

M

Mache 69

papier 69

coarse 69

dextrin 69

asbestos 70

Materials

Metal molds 19

casting, hot 22

cold 21

hydraulic 22

Mercuric chloride 77

Metalplating insects 63

Methyl methacrylate 78

Micrometer 77

Modelling tools 77

Models 42-46

enlarged of adult sawfly 46

of sawfly larva 46

Mother mold

N

Net, insect 1

O

Orthoptera, preserving 5

P

Painting casts 46

Paints 78

dry colors 78

oil colors 78

water colors 78

Paraffin wax 78

Pestproofing insects 62

Petroleum jelly 10

Phenol 78

Plant assembly 37

Plant preserving 6

dry for herbarium 6,7

wet in preserving fluid 65

Plaster 8

casting 18

characteristics of 8

jackets 16

molds 9

Plastic casting

from rubber molds 34

sheet casting 34,35

Walters' method 20

Poison bottles 1

86

Page

Preserving insects

Coleoptera 6

Diptera 6

immature forms

Lepidoptera 5

Orthoptera 5

Pumice 78

R

Rearing insects 1

Releasing plastic casts 31

S

Sculpturing supplies 78

Separators 68, 69

Shaping plastic casts 31

Shipping 59

exhibits 59

foliage 59

fruit 59

insects 59

vegetables 59

Solder

jewellers' 78

Soldering iron 77

Soldering flux 65

Page

Solvents 78

Sources of supplies 77

Spraying leaves

Swivel lens 77

T

Tenite pellets 78

Thermometers 77

Thinners 70

Tools 71

Trimmer, paper 54

Trimming leaves 27

Tweezers 71

V

Vasculum 75

Vise 76

W

Wax, bees 78

paraffin 78

press 73

X

Xylol 79

87

LIBRARY / BIBLIOTHEQUE

AGRICULTURE CANADA OTTAWA K1A OC5

3 TD73 000M53Mb b