[6] _Anthrenus verbasci_ L.
The varied carpet beetle is similar in shape to the common carpet
beetle,[7] but is a trifle smaller. It is called the "varied" carpet
beetle because the color pattern on the back of the beetle varies
considerably with the arrangement of the white, brownish, and yellowish
scales. Figure 7 presents a common arrangement of the scales. The
underside of the body is thickly clothed with white scales. This insect
is a European pest now well established in widely separated parts of
the United States. It has been found more often perhaps feeding upon
seeds in museums than upon clothing, though its larvæ do attack woolen
goods, feathers, hair, and silks.
[7] _Anthrenus scrophulariae_ L.
The larvæ are not unlike other carpet beetle larvæ of the genus
Anthrenus. In Figures 8 and 9 are shown the newly hatched and the
mature larvæ. When unmutilated, they posses on each side at the end of
the body three dense tufts of bristles and hairs. If suddenly alarmed,
the larvæ erect these tufts and spread the bristles and hairs out so as
to form beautiful round balls.
[Illustration: Fig. 8.--Varied carpet beetle: Dorsal view of newly
hatched larva. Greatly enlarged.]
During late spring and early summer, when the insect transforms to the
adult stage in greatest numbers, the adults are driven by instinct to
seek the bright sunshine and the pollen of certain flowers. In this
respect they are not unlike other species of carpet beetles, the adults
of which may be found also upon flowers. Some think that Viburnum or
Spiraea bushes planted near the house will lure carpet beetles from the
house. It is probably true, however, that the beetles, before leaving
the house, lay a large percentage of their eggs, so that the attraction
the sun and flowers have for them is of so little practical value to
the householder that it is not worth while to depend upon flowers to
lure the adults from the house.
The varied carpet beetle in the adult stage flies about in tremendous
numbers. During May, 1922, the writer could capture them by the
thousands upon at least 30 species of flowers found in public gardens
in Washington, D. C. Single white roses often attracted more than 100
beetles, while a single stalk of a common herbaceous Spiraea harbored
more than 1,000 specimens. The beetles often fly in large numbers
rather high above the ground. A gentleman[8] after painting a portion
of the tin roof of his house during early May returned 24 hours later
to complete the painting, only to find that during the interim an
average of two varied carpet beetles to the square inch had become
entangled in the fresh paint. The writer observed two adults fly into
his city apartment in Washington through an open window during early
March, 1922. These flights of adults are of extreme importance to the
householder, because they emphasize how readily carpet beetles may
spread from house to house during spring and early summer. Window
screens will exclude all except the smallest specimens if they fit
tightly, but the average removable screen does not fit tightly enough
to prevent adult carpet beetles from crawling into the house between
screen and window frame.
[8] H. S. Barber.