The male White-legged Damselfy (Platycnemis pennipes) has a blue abdomen that is often paler than other blue damselflies.
Immature males and immature females are mostly creamy white. 
Females take on a greenish yellow colour on maturity.
Mature males and females differ from most other blue damselflies in having pale brown pterostigmata and broad and flattened white tibiae (lower part of the legs) giving a feather like appearance.

Hortobágy-Halastó, Hortobágy National Park, Hungary, 2 May 2019