The Wikipedia article of the day for June 24, 2016 is
Horse-fly.
Horse-flies are large flies of the family Tabanidae that feed mainly on nectar. The males have weak mouthparts; only the females bite animals, including humans, to obtain enough protein from the blood to produce eggs. For this they use a stout stabbing organ and two pairs of sharp cutting blades to bite, and a spongelike part to lap up the blood that flows from the wound. They can transfer blood-borne diseases from one animal to another. They can also reduce growth rates in cattle and lower the milk output of cows if suitable shelters are not provided; some animals have lost up to 300 millilitres of blood in a single day to the insects. Horseflies prefer to fly in sunlight, avoiding dark and shady areas, and are inactive at night. They are found all over the world except for some islands and the polar regions. The larvae are predaceous and grow in semiaquatic habitats. Horse-flies have appeared in literature since Aeschylus in Ancient Greece wrote about them driving people to madness. Gadflies (horse-flies and botflies) are mentioned in Shakespeare's plays King Lear and Antony and Cleopatra.
