The scarlet skimmer or ruddy marsh skimmer (Crocothemis servilia) is a species of dragonfly of the family Libellulidae, native to east and southeast Asia and introduced to Jamaica, Florida, and Hawaii.
There are two known subspecies: Crocothemis servilia servilia (Drury, 1773) and Crocothemis servilia mariannae Kiauta, 1983. C. s. mariannae lacks the mid-dorsal black stripe.
It is a medium sized dragonfly. The male is blood-red, with a thin black line along the mid-dorsal abdomen in the nominate subspecies. Its eyes are blood-red above, purple laterally. Thorax is bright ferruginous, often blood-red on dorsum. Anal appendages are blood-red. Female is similar to the male, but with olivaceous-brown thorax and abdomen. The black mid-dorsal carina is rather broad.
It breeds in ponds, ditches, marshes, open swamps and rice fields.