Thread subject: Diptera.info :: Helophilus pendulus

Posted by Tony Irwin on 15-08-2006 23:56
#5

Yes, I'd say H. pendulus.
The three spots between the compound eyes are the ocelli (or simple eyes). Almost all flies have ocelli, usually arranged in a triangle, and sitting on a more or less clearly defined plate called the ocellar triangle. Sometimes the ocelli sit on a raised bump called the ocellar tubercle, and often they have a pair of bristles, arising between the ocelli and usually pointing forwards. I tell you all this becasue the position of the ocelli and the length of the ocellar bristles are often used as identification characters.
Sometimes the frons (the area in front of the ocelli, and above the antennae) has one or more bare shining patches. These patches are called calli (one is called a callus), and they are found in flies like Tabanidae and Therevidae, and can be very useful identification characters.

Edited by Tony Irwin on 16-08-2006 00:07