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8 R NO. 36, SECOND SERIES, REVISE. Issued January 15, 1908.

nited States Department of Agriculture,
BUREAU OF ENTOMOLOGY,

L. O. HOWARD, Entomologist and Chief of Bureau.

THE TRUE CLOTHES MOTHS.
(Tinea pellionella et al.)

By C. L. MARLATT
e ’

Entomologist and Acting Chief in Absence of Chief.

The destructive work of the larve of the small moths commonly
known as clothes moths, and also ag carpet moths, fur moths, ete., in
woolen fabrics, fur, and similar material during the warm months of
summer in the North, and in the South at any season, is an altogether
too common experience. The preference they so often show for woolen
or fur garments gives these insects a much more general interest than
is perhaps true of any other household pest.

The little yellowish or buff-colored moths sometimes seen flitting
about rooms, attracted to lamps at night, or dislodged from infested
garments or portieres, are themselves harmless enough, and in fact their
mouth-parts are rudimentary, and no food whatever is taken in the
winged state. The destruction occasioned by these pests is, therefore,
limited entirely to the feeding or larval stage. The killing of the
moths by the aggrieved housekeeper, while usually based on the wrong
inference that they are actually engaged in eating her woolens, is,
nevertheless, a most valuable proceeding, because it checks in so much
the multiplication of the species, which is the sole duty of the adult
insect.

The clothes moths all belong to the group of minute Lepidoptera
known as Tineina, the old Latin name for cloth worms of all sorts, and
are characterized by very narrow wings fringed with long hairs. The
common species of clothes moths have been associated with man from
the earliest times and are thoroughly cosmopolitan. They are all
probably of Old World origin, none of them being indigenous to the
United States. That they were well known to the ancients is shown
by Job’s reference to ‘‘a garment that is moth eaten,” and Pliny has
given such an accurate description of one of them as to lead to the
easy identification of the species. That they were early introduced
into the United States is shown by Pehr Kalm, a Swedish scientist,
who took a keen interest in house pests. He reported these tineids
to be abundant in 1748 in Philadelphia, then a straggling village, and
says that clothes, worsted gloves, and other woolen stuffs hung up all
summer were often eaten through and through by the worms, and furs
were so ruined that the hair would come off in handfuls.

2

What first led to the association of these and other household pests
with man is an interesting problem. In the case of the clothes moths,
the larvee of all of which can, in case of necessity, still subsist on
almost any dry animal matter, their early association with man was
probably in the role of scavengers, and in prehistoric times they
probably fed on waste animal material about human habitations and
on fur garments. The fondness they exhibit nowadays for tailor-made
suits and other expensive products of the loom is simply an illustra-
tion of their ability to keep pace with man in his development in the
matter of clothing from the skin garments of savagery to the artistic
products of the modern tailor and dressmaker.

Three common destructive species of clothes moths occur in this
country. Much confusion, however, exists in all the early writings
on these insects, all three species being inextricably mixed in the
descriptions and accounts of habits. Collections of these moths were
submitted some years
ago by Professors
Fernald and Riley to
Lord Walsingham, of
Merton Hall, Eng-
land, the world’s au-
thority on tineids,
and from the latter’s
careful diagnosis it is
now possible to sepa-

rate and recognize
Fic. 1.—Tinea pellionella: Above, adult; at right, larva; at the different species
left, larvain case. Enlarged (from Riley).

easily.

The common injurious clothes moths are the case-making species
(Tinea pellionella L.), the webbing species or Southern clothes moth
( Tineola biselliella Hummel), and the gallery species or tapestry moth
( Trichophaga tapetzella L.).

A few other species, which normally infest animal products, may
occasionally also injure woolens, but are not of sufficient importance
to be here noted.

THE CASE-MAKING CLOTHES MOTH.

The case-making clothes moth (Tinea pellionella L.) (fig. 1) is the
only species which constructs for its protection a true transportable case.
It was characterized by Linneus, and carefully studied by Réaumur,
early in the last century. Its more interesting habits have caused it
to be often a subject of investigation, and its life history will serve to
illustrate the habits of all the clothes moths.

The moth expands about half an inch, or from 10 to 14 mm. _ Its
head and forewings are grayish yellow, with indistinct fuscous spots on

the middle of the wings. The hind wings are white or grayish and
silky. It is the common species in the North, being widely distributed
and very destructive. Its larva feeds on woolens, carpets, etc., and is
especially destructive to furs and feathers. In the North it has but one
annual generation, the moths appearing from June to August, and, on
the authority of Professor Fernald, even in rooms kept uniformly heated
night and day it never occurs in the larval state in winter. In the
South, however, it appears from January to October, and has two or
even more broods annually.

The larva is a dull white caterpillar, with the head and the upper
part of the next segment light brown, and is never seen free from its
movable case or jacket, the construction of which is its first task. If
it be necessary for it to change its position, the head and first segment
are thrust out of the case, leaving the thoracic legs free, with which it
crawls, dragging its case after it, to any suitable situation. With the
growth of the larva it becomes necessary from time to time to enlarge
the case both in length and circumference, and this is accomplished in
a very interesting way. Without leaving its case the larva makes a slit
halfway down one side and inserts a triangular gore of new mate-
rial. A similar insertion is made on the opposite side, and the larva
reverses itself without leaving the case and makes corresponding slits
and additions in the other half. The case is lengthened by successive
additions to either end. Exteriorly the case appears to be a matted
mass of small particles of wool; interiorly it is lined with soft whitish
silk. By transferring the larva from time to time to fabrics of different
colors the case may be made to assume as varied a pattern as the
experimenter desires, and will illustrate, in its coloring, the peculiar
method of making the enlargements and additions described.

On reaching full growth the larva attaches its case by silken threads
to the garment or other material upon which it has been feeding, or
sometimes carries it long distances. In one instance numbers of them
were noticed to have scaled a 15-foot wall to attach their cases in an
angle of the cornice of the ceiling. It undergoes its transformations to
the chrysalis within the larval case, and under normal conditions the
moth emerges three weeks later, the chrysalis having previously worked
partly out of the larval case to facilitate the escape of the moth. The
latter has an irregular flight and can also run rapidly. It has a distinct
aversion to light, and usually conceals itself promptly in garments or
crevices whenever it is frightened from its resting place. The moths
are comparatively short-lived, not long surviving the deposition of their
eggs for a new generation of destructive larve. The eggs are minute,
not easily visible to the naked eye, and are commonly placed directly
on the material which is to furnish the larvee with food. In some cases
they may be deposited in the crevices of trunks or boxes, the newly
hatched larve entering through these crevices.

In working in feathers this insect occasionally causes a felting very
similar to that produced by the black carpet beetle, Attagenus piceus Ol.

The protection afforded by the seclusion of this insect in houses does
not prevent its having insect enemies, and at least two hymenopterous
parasites have been reared in this country from its larval cases. These
are Hyperacmus tinew Riley MS., and Apanteles carpatus Say, both
reared from specimens collected in Michigan.

THE WEBBING, OR SOUTHERN CLOTHES MOTH.

The webbing, or Southern clothes moth (Tineola biselliella Hum-
mel) (fig. 2) is the more abundant and injurious species in the latitude
of Washington and southward. It occurs also farther north, though
in somewhat less numbers than the preceding species. It presents two |
annual broods even in the Northern States, the first appearing in June

_ from eggs deposited in May, and

mae yt __- the second in August and Sep-

; =3 tember. It is about the size of
pellionella. The forewings are,
however, uniformly pale ocher-
ous, without markings or spots.
Its larva feeds on a large variety
of animal substances—woolens,
po as hair, feathers, furs, and in Eng-
ad land it has even been observed

Fig. 2.—Tineola biselliella: Moth, larva, cocoon, to feed on cobwebs in the corners
and empty pupa skin. Enlarged (from Riley). ;

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ah Nay, A NNNOOwenes 8

of rooms, and in confinement has
been successfully reared on this rather dainty food substance. The
report that it feeds on dried plants in herbaria is rather open to ques-
tion, as its other recorded food materials are all of animal origin.

Frequently this species is a very troublesome pest in museums, partic-
ularly in collections of the larger moths. Prof. F. M. Webster, of
this Bureau, once had some of his large moths badly riddled by its larve,
and Hagen also records it as feeding on insect collections. Doctor
Riley reared it in conjunction with the Angoumois grain moth (Sito-
troga cerealella) from grain, it being apparent that its larvee had sub-
sisted on dead specimens of the grain moth. It is very likely to attack
large Lepidoptera on the spreading board, and has, in fact, been carried
through several generations on dried specimens of moths.

Its general animal-feeding habit is further indicated by the interest-
ing case reported by Dr. J. C. Merrill, U. S. A.. who submitted a sam-
ple can of beef meal which had been rejected as “ weevilly.”’ The
damage proved to be due to the larvee of Tineola biselliella, and goes
to substantiate the theory already advanced that clothes moths were
scavengers in their earliest association with man.

eb |

The larva of this moth constructs no case, but spins a silky. or more
properly cobwebby, path wherever it goes. When full grown it builds a
cocoon of silk, intermixed with bits of wool, resembling somewhat the
case of pellionella, but more irregular in outline. Within this it under-
goes its transformation to the chrysalis, and the moth in emerging
leaves its pupal shell projecting out of the cocoon as with the preceding
species.

THE TAPESTRY MOTH.

The tapestry moth (Trichophaga tapetzella L.) (fig. 3) is rare in
the United States. It is much larger than either of the other two
species, measuring three-fourths inch in expansion of wings, and is
more striking in coloration. The
head is white, the basal third of
the forewings black, with the ex-
terior two-thirds of a creamy white,
more or less obscured on the mid-
dle with gray; the hind wings are

pale gray.
This moth normally affects rather FiG. 3.—Trichophaga tapetzella: Adult moth. En-
coarser and heavier cloths than the larged (from Riley).

smaller species and is more apt to occur in carpets, horse blankets, and
tapestries than in the finer and thinner woolen fabrics. It also affects felt-
ing, furs, and skins, and is a common source of damage to the woolen
upholstering of carriages, being rather more likely to occur in carriage
houses and barns thanin dwelling houses. Its larva enters directly into the
material which it infests, constructing burrows or galleries, which it lines
more or less completely with silk. Within these galleries it is protected
and concealed during its larval life, and later undergoes its transforma-
tions without other protection than that afforded by the gallery. The
damage is due as much or more to its burrowing than to the actual
amount of the material consumed for food.

One of the parasites reared from pellionella (Apanteles carpatus Say)
has also been reared from this species at St. Louis, Mo.

REMEDIES.

There is no easy method of preventing the damage done by clothes
moths, and to maintain the integrity of woolens or other materials
which they are likely to attack demands constant vigilance, with fre-
quent inspection and treatment. In general, they are likely to affect
injuriously only articles which are put away and left undisturbed for
some little time. Articles in daily or weekly use, and apartments fre-
quently aired and swept, or used as living rooms, are not apt to be
seriously affected. Carpets under these conditions are rarely attacked,
except sometimes around the borders, where the insects are not so much

6

disturbed by walking and sweeping. Agitation, such as beating, shak-
ing, or brushing, and exposure to air and sunlight, are old remedies
and still among the best at command. Various repellents, such as
tobacco, camphor, naphthaline cones or balls, and cedar chips or sprigs,
have a certain value if the garments are not already stocked with eggs
or larvee. The odors of these repellents are so disagreeable to the
parent moths that they are not likely to come to deposit their eggs as
long asthe odorisstrong. As the odor weakens the protection decreases,
and if the eggs or larvee are already present, these odors have no effect
on their development; while if the moths are inclosed with the stored
material to be protected by these repellents, so that they can not
escape, they will of necessity deposit their eggs, and the destructive
work of the larve will be little, if at all, restricted. After woolens have
been given a vigorous and thorough treatment and aired and exposed
to sunlight, however, it is of some advantage in packing them away to
inclose with them any of the repellents mentioned. Cedar chests and
wardrobes are of value in proportion to the freedom of the materia]
from infestation when stored away; but, as the odor of the wood is
largely lost with age, in the course of a few years the protection greatly
decreases. Furs and such garments may also be stored in boxes or
trunks which have been lined with heavy tar paper used in buildings.
New papering should be given to such receptacles every year or two.
Similarly, the tarred paper moth bags obtainable at dry-goods houses
are of some value; always, however, the materials should first be sub-
jected to the treatment outlined above.

To protect carpets, clothes, and cloth-covered furniture, furs, ete.,
these should be thoroughly beaten, shaken, brushed, and exposed as
long as practicable to the sunlight in early spring, either in April, May,
or June, depending on the latitude. The brushing of garments is
a very important consideration, to remove the eggs or young larve
which might escape notice. Such material can then be hung away
in clothes closets which have been thoroughly cleaned, and, if neces-
sary, sprayed with benzine about the cracks of the floor and the
baseboards. If no other protection be given, the garments should be
examined at least once a month during summer, brushed, and, if neces-
sary, exposed to the sunlight.

It would be more convenient, however, so to inclose or wrap up such
material as to prevent the access of the moths to it, after it has once
been thoroughly treated and aired. This can be easily effected in the
case of clothing and furs by wrapping tightly in stout paper or inclos-
ing in well-made bags of cotton or linen cloth or strong paper. Doctor
Howard has adopted a plan which is inexpensive, and which he has
found eminently satisfactory. For a small sum he secures a num-
ber of the large pasteboard boxes, such as tailors use, and in these
packs away all winter clothing, gumming a strip of wrapping paper

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around the edge, so as to seal up the box completely and leave no
cracks. These boxes with care will last many years. With thorough
preliminary treatment it will not be necessary to use the tar-impregnated
paper sacks sold as moth protectors, which may be objectionable on
account of the odor.

In the case of cloth-covered furniture and cloth-lined carriages,
which are stored or left unused for considerable periods in summer, it
will probably be necessary to spray them twice or three times, viz, in
April, June, and August, with benzine or naphtha, to protect them
from moths. These substances can be applied very readily with any
small spraying device. and will not harm the material, but caution
must be exercised on account of their inflammability. Another means
of protecting such articles is to sponge them very carefully with a dilute
solution of corrosive sublimate in alcohol, made just strong enough not
to leave a white stain.

The method of protection adopted by one of the leading furriers of
Washington, who also has a large business and experience in storing
costly furs, etc., is practically the course already outlined. Furs when
received are first most thoroughly and vigorously beaten with small
sticks, to dislodge all loosened hair and the larvee or moths. They are
then gone over carefully with a steel comb and packed away in large
boxes lined with heavy tar roofing paper, or in closets similarly lined
with this paper. An examination is made every two to four weeks,
and, if necessary at any time, any garment requiring it is rebeaten
and combed. During many years of experience in this climate, which
is especially favorable to moth damage, this merchant has prevented
any serious injury from moths.

COLD STORAGE,

The best method of protection, and the one now commonly adopted
by dealers in carpets, furs, etc., is cold storage. In all large towns
anyone can avail himself of this means by patronizing storage com-
panies, and safety will be guaranteed.

The most economical degree of cold to be used as a protection
from clothes moths and allied insects destructive to woolens and furs
has been definitely determined by the careful experiments carried out
at the instance of Doctor Howard by Dr. Albert M. Read, manager of
a large storage warehouse company in Washington, D.C. These experi-
ments demonstrated that a temperature maintained at 40° F. renders
the larval or other stages of these insects dormant and is thoroughly
effective. The larvee, however, are able to stand a steady temperature
as low as 18° F. without apparently experiencing any ill results. Doctor
Read’s experiments have extended over two years, and his later results
as reported by Doctor Howard are very interesting. They have demon-
strated that while a temperature kept uniformly at 18° F. will not destroy

HSONIAN INSTITUTION LIBRARIES

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the larvee of Tineola biselliella or of the black carpet beetle (Attagenus
piceus), ° an alternation of a low temperature with a comparatively
high one invariably results in the death of the larvee of these two insects.
For example, if larvee of either which have been kept at a temperature
of 18° F. are removed to a temperature of 40° to 50° F., they will
become slightly active and, when returned to the lower temperature
and kept there for a little time, will not revive upon a retransfer to the

warmer temperature.”’

It is reeommended, therefore, that storage companies submit goods
to two to three changes of temperature as noted before placing them
permanently in an apartment kept at a temperature of from A0® to 422 ik.
The maintenance of a temperature lower than the last indicated is need-
less and a wasteful expense. Where the cost of cold storage is not an
item to be seriously considered, the adoption of this method for pro-
tection of goods during the hot months is strongly recommended.

Approved :
JAMES WILSON,
Secretary of Agriculture.

WASHINGTON, D. C., December 20, 1907.

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