The members of the order Diptera are numerous, with approximately 25,00 species being present in North America.  The word Diptera has a Greek root and means "two wings".  The order is sub-divided into two sub-orders: Brachycera - the short horned flies and Nematocera - the long horned flies.  In general flies in the sub-order Brachycera have robust bodies and antennae that are short and have minimal segments.  An example of a fly in this sub-order is a Horse Fly.  While the Nematocera are generally long legged, fine bodied with lengthy antennae that have numerous segments.  The Mosquito is an example of a fly that fits into this sub-order.  All flies have a primary set of flight wings connected to the mesothorax and a second set of knob like vestigial wings or halteres.  Although the exact function of the halteres is not known, it has been suggested that they act as gyroscopic indicators of the fly's position while it is airborne.  The majority of higher flies have sponge-like mouthparts which they use to sop up liquid foods. (Marshall, 2006 & Imes, 1992)

Flies in the Fossil Record

Fly Anatomy

Fly Metamorphosis

Habitat and Food

References