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.
The range of a viola is three and one third octaves. The range goes from one octave below middle C to the E note that is two and a half octaves above middle C. This range is considered a moderate one for a stringed instrument. An octave is a series of 12 notes which are referred to as a combination of whole steps and half steps.