[3] _Anthrenus scrophulariae_ L.
The common carpet beetle was known as _the_ carpet beetle in the years
following its introduction into America when floors were more commonly
than, now covered entirely with carpets that were tacked down along the
edges, thus giving the larvæ an undisturbed shelter favorable to their
development. Originally a pest in Europe, where it is still common, it
was introduced into this country about 1874, probably at Boston and New
York simultaneously. No stage of this common carpet beetle is longer
than three-sixteenths to one-fourth of an inch. The general proportions
of larva, pupa, and adult are shown in Figure 1. The rich reddish brown
larvæ are clothed with stiff dark brown hairs which are longer around
the sides, and still longer at the ends, than upon the back.
[Illustration: Fig. 1.--The common carpet beetle: _a_, Larva, dorsal
view; _b_, pupa within larval skin; _c_, pupa, ventral view; _d_,
adult. All enlarged (Riley.)]
The larvæ feed upon carpets and woolens (Fig. 2), furs, feathers (Fig.
3), bristles, and silks. They remain secluded in dark places, hidden
beneath carpets or in the folds of garments. They eat irregular holes
in fabrics, but in carpets tacked to floors they are more likely to eat
slits following cracks. They never cause a webbing on the fabric.
[Illustration: Fig. 2.--Typical carpet beetle damage to woolen cloth.
For injury to feathers see Fig. 3.]
While most conspicuous in the Northern States, this carpet beetle is
frequently found in the latitude of Washington, D. C, and southward
Specimens have, recently been sent from Texas and Florida. In a
Washington storehouse the contents of a trunk closed for several years
were found badly damaged by the larvæ.
The following account[4] is just as applicable to-day as when written
many years ago.
[4] Howard, L. 0., in Bulletin 4, new series, Division of Entomology,
United States Department of Agriculture, pp. 58-59. 1896.
The adult insect is a small, broad-oval beetle, about three-sixteenths
of an inch long, black in color, but is covered with exceedingly
minute scales, which give it a marbled black-and-white appearance.
It also has a red stripe down the middle of the back, widening into
projections at three intervals. When disturbed it "plays 'possum,"
folding up its legs and antennæ and feigning death As a general thing
the beetles begin to appear in the fall, and continue to issue, in
heated houses, throughout the winter and following spring. Soon after
issuing they pair, and the females lay their eggs in convenient spots.
The eggs hatch, under favorable conditions, in a few days, and the
larvæ, with plenty of food, develop quite rapidly. Their development
is retarded by cold weather or lack of food, and they remain alive
in the larval state, in such conditions and particularly in a dry
atmosphere, for an almost indefinite period molting frequently and
feeding upon their cast skins. Under normal conditions, however the
skin is cast about six times, and there are, probably, in the North,
not more than two annual generations. When the larva reaches full
growth the yellowish pupa is formed within the last larval skin.
Eventually this skin splits down the back and reveals the pupa,
from which the beetle emerges later. The beetles are day fliers,
and when not engaged in egg laying are attracted to the light. They
fly to the windows, and may often be found upon the sills or panes.
Where they can fly out through an open window they do so, and are
strongly attracted to the flowers of certain plants, particularly
the family Scrophulariaceæ but also to certain Composite, such as
milfoil (_Achillea millefolium_). The flowers of Spiræa are also
strongly attractive to the beetles. It is probable, however, that this
migration from the house takes place, under ordinary circumstances
after the eggs have been laid.
[Illustration: Fig. 3.--Feathers damaged by fabric pests. Injury
has been done here by clothes moths and carpet beetles. They reduce
feathers to a mat-like mass.]
In Europe the insect is not especially noted as a household pest,
probably owing to the fact that carpets are seldom tacked down. In
fact, the writer believes that only where carpets are extensively used
in this way are the conditions favorable for the great increase of this
insect. Carpets once tacked down are seldom taken up for a year, and in
the meantime the insect develops uninterruptedly. With the more general
use of polished floors, and rugs which are often taken up and beaten,
there is little doubt that the "buffalo bug" will eventually cease to
be a household insect of importance. The insect is known in Europe as
infesting museums, but has not acquired this habit to any great extent
in this country. It is known to have this habit in Cambridge, Mass.,
and Detroit, Mich., as well as in San Francisco, Calif., but not in
other localities. In each of these three cases it was imported from
Europe in insect collections.