Firebrats

Firebrats are wingless insects, belonging to the order Thysanura, considered to be both primitive and unspecialized compared to other insects. They have a somewhat flattened, tapered torpedo-shaped body which is covered with metallic-looking scales.
They are sometimes called "bristle-tails", a name derived from three long sensory appendages attached to the hind end of the body Firebrats are larger than Silverfish and have a mottled appearance.
The Firebrat tends to select furnace rooms, and walls near radiators or steam pipes, where the temperature range is between 27℃ and 41℃. They feed quietly on starchy substances such as glue, wall paper paste and starchy foods.
They will also eat biscuits and bread crumbs. Paper, textiles, and other cellulose products may also form part of their diet.
Damage is characterized by irregular holes.They are sometimes found in wash basins and bath tubs, not because they have entered by way of the drain, but because they are incapable of climbing a glazed vertical surface once they have fallen in from above.