The furca of Sargus

Hi, I am trying to identify a female of Sargus 'irridatus/cuprarius', so, using 'Soldierflies and their Allies', I need to locate the furca. Where is this located? I have more or less cleared the tip of the abdomen without the structure being obviously evident, assuming that is where it should be found, but perhaps that is wrong? Also, what is its function?

Phil Porter

Comments

Hi Phil, the furca should be within the tip of the abdomen.

If you download the recording scheme ID guide to Sargus and look for female of S. cuprarius on page 9, there is an image of a dissected furca provided by Richard Dickson. Download from www.brc.ac.uk/soldierflies-and-allies/id-guides

The only definition I can find for  "furca" is "In most Nematocera and Orthorrhapha, the sternite 9 is reduced to a V-shaped or Y-shaped sclerite and is called genital fork or vaginal apodeme or furca" (which is taken from www.giand.it/diptera/morph/). I don't know what its function is, would be interested to know if anyone can tell us.