let's go through them and get this fixed.
This is an adult fungus gnat.
Fungus gnat larvae.
Fungus gnats are small, dark, short-lived flies, of the families Sciaridae, Diadocidiidae, Ditomyiidae, Keroplatidae, Bolitophilidae, and Mycetophilidae (order Diptera); they are sometimes placed in the superfamily Mycetophiloidea.
The larvae of fungus gnats feed on plant roots and fungi, which aids in the decomposition of organic matter. The adults are 2–5 mm long and are important pollinators that can help spread mushroom spores as well as plant pollen. It is well documented that they carry on their feet such diseases as pythium.
Fungus gnats are typically harmless to healthy plants but cause more of a nuisance to the gardener but can inflict extensive damage to seedlings an small plants; their presence can be indicative of more serious problems. In houseplants, the presence of fungus gnats may indicate overwatering; they may be feeding on roots that have sat in stagnant water too long and are thus rotting, or the gnats may be attracted to fungus growing in saturated topsoil. Consequently, allowing the soil to dry may reduce their numbers.
There are a number of ways to break the fungus gnat reproduction cycle using chemicals such an gnat off etc but I always found that a simple layer of sharp sand on top of the soil works best. This acts like little knives to the gnats an slashes there wings and legs which deters them from getting back into the soil to lay there eggs.
Simply put 1/2 inch of sand on top of your soil and allow it to dry.
You can also add a few potatoes slices to the soil which will attract some of the larvae to it which you then just remove and chuck away.
Also fly sticky strips that hang from the walls or ceiling will catch any left over gnats hanging about.
There are also a few predator mites that will eat the gnat larvae which will also clean up the soil.
Introducing Hypoaspis miles mites or applying the biological larvicide Bacillus thuringiensis (subspecies israelensis) to kill the gnats in their larval stage; the larvacide must be applied weekly as a soil drench for 4–5 weeks. Annually drenching the soil in an insecticidal soap; Detergents and the nicotine from tobacco brewed into a toxic tea are used by some people to control fungus gnats to good effect.
I use the hypo mites on my girls just as precautionary measure after having the lil fuckers once before... I had to get some for my snakes too so I get 2 uses out of them 
they do a great job too.... thanks for sharing matey 
