Adult dragonflies will eat any insect as long as they are able to catch it. While they usually eat mosquitoes and midges, they also eat butterflies, moths, beetles, bees, flies, and even other dragonflies. The general rule is that larger dragonflies will eat insects of body weight daily.
Origin of the name Viola: Derived from the Latin viola (a violet). The name has been in use since the Middle Ages but did not become common until the middle of the 19th century when the use of flower names came into vogue. From A World of Baby Names by Teresa Norman.
Range. There are four strings on the viola which are tuned a Perfect 5th apart. The lowest is C then G, D and A is the top string. The lower strings have a richer, darker sound and to exploit this it is quite common for composers to write that a particular phrase should be played on a particular string.