@NicoleManson. If it is a Soldier Fly, then the males have a sperm tube at the end of the abdomen and the females have an ovipositor (egg laying tube). But I personally would not describe either as large. If you can photos of the insect on its back and possibly its side, then we would be much better placed to identify it. There are a number of black wasps that can look similar, but tend to be larger. The wasps seldom ever sit still and look almost ‘nervous’ the way they continually move about. Soldier Flies, on the hand, sit quietly for extended periods of time. Wasps also possess a really tight constriction between the thorax (middle section to which the legs and wings are attached) and the abdomen (main body end of the insect) – known not surprisingly as a “wasp waist”.