Field plate · Ctenocephalides felis
Cat flea
The flea on nearly every dog and cat in Pennsylvania, despite the name. A summer problem that starts on the pet and lives in the carpet.
Plate 21 of 28. Drawn in profile to the identification marks named below; the scale rule is a drawing convention — sizes are given in the text.
Identification marks
Adults 1–3 mm, dark brown, laterally flattened, wingless, with powerful hind legs. Eggs are white and pearl-like and fall where the pet rests; larvae are tiny pale worms in carpet and floor cracks, avoiding light.
Look-alikes it is confused with
Dog flea (nearly identical, far less common — the cat flea rules both hosts), human flea (rare here), and bed bugs, which do not jump and live at the bed, not on the pet.
Where it hides in a house
Only about one in twenty fleas in an infested house is an adult on the pet. The rest are eggs, larvae, and cocoons in carpets, sofa seams, pet bedding, and basement floors where pets sleep — and the cocoon stage can wait out months of treatment.
Health & property risk, stated plainly
Bites, flea-allergy dermatitis in pets (a veterinary misery of itching and hair loss), anaemia in kittens and puppies under heavy loads, and the tapeworm a pet picks up by swallowing a flea while grooming.
What actually works
Treat every pet in the house on a veterinary program, on schedule, for months — not once. Wash pet bedding hot, vacuum carpets and sofa bases thoroughly and often (vibration also triggers cocoons to hatch into a treated environment), and empty the vacuum outside.
What doesn't
Flea bombs that coat the room while eggs and cocoons sit untouched in the carpet base, flea collars as the whole plan, and treating the dog while the indoor cat — the silent reservoir — goes untreated.
When to call a licensed pro
Call a pro when the house is heavily infested, when a rental is turning over with fleas from the previous tenant's pets, or alongside veterinary care when the pet's skin is raw.