Tabanus sp.
Closely related species to Tabanus longiglossus

Species belonging to the genus Tabanus have developed into the one of the largest genus of the “True flies.”  They are very strong fliers, which allows the females to fly just out of reach of their vertebrate prey and the males to rapidly fly from flower to flower feeding on nectar (Arnett 1985).  One species that is closely related to Tabanus longiglossus (in the same genus) can reach flight speeds of 150 km/hour (Resh and Carde 2003)!  Some adaptations that characterize the genusTabanidae, wing Tabanus may have arose allowing for their rapid flight.  One of these adaptations is a body that lacks bristles.  Another adaptation is their distinctively large calypteres (lobes located at the posterior side of the wing) (Arnett 1985).  We believe that there should be some additional study done to see if there is any correlation between their unusually large calypteres and body that largely lacks bristles (these are unique to this genus) that result in their increased flight speed.  Tabanus longiglossus wings are similar to the rest of the flying insects given that they are thin and membranous.  Just like the rest of the species falling under the order Diptera, they have only one pair of primary flight wings called patent flight wings and a reduced set of halteres, which are used for balance in flight (Wilegmann, 2007).  Their wings are almost transparent and either colorless or smoky (Resh and Carde 2003).  This species also has an annulated, as opposed to a segmented, antennae (Borror and White 1970).  Another adaptation Tabanus longiglossus has developed is their large compound eyes.  They are very large and compose almost all of their head.  They are generally green or purple earning them the name “green heads.” To learn other nicknames for horseflies you can go to the interesting facts page of this website.  The eyes are separated in the females, but are united dorsally in the males (Arnett 1985).  These eyes give them an acute sense of sight allowing the females to use visual cues to locate host that they can feed upon.  They are also, amazingly, able to sense plumes of carbon dioxide produced during respiration of the vertebrates they seek to feed upon (Resh and Carde 2003).