Bites of bird fleas on the skin of the thigh. The reddened itchy papules persist for a long time. Line formations are usual. A flea lands on the skin accidentally and bites a couple of times. After establishing the ”species” they move on to look for their proper host animals. Pets bring them indoors in their coats, and fleas find their way under the clothes of outdoor enthusiasts especially early in the spring and late in the autumn.